Assuming that the interest relates to Field Uniforms worn at the start of that war, the standard form of these was established by the 1919 Uniform Regulations ( published 1920). Khaki overall with oxidised metal buttons, brown boots and leather accoutrements, this was to be the basic form for all arms and services within the Polish Army.
If you search under. PRZEPIS UBIORU POLOWEGO WOJSKA POLSKIEGO 1919 and access the entry under http://www.1920.fora.pl you will see the regulations which have, at the bottom of the page some original illustrations of this basic uniform.
The introduction of these regulations began to establish some regularity in both uniform and equipment to a situation which arose out of the inheritance by the army of captured stocks drawn from Austro-Hungarian, German and Russian supplies.
Prior to the introduction of these regulations, attempts had been made, to achieve some sort of local standardisation. Thus at regimental level units tended to be dressed according to the stocks they had inherited at the start of the 1919 campaign, ( Regiment A in khaki, regiment B in light grey). However depending on the availability of supply, the means to achieve supply through local tailoring and the availability of captured stocks, quite a large variance from this standard can be observed in photographs taken at the time.
By the start of the 1920 campaign, further stocks were beginning to flow into the country, from abroad. So even if standardisation of form was achieved, there was variance within it. Unit A may have been dressed in British 1902 tunics, B in American Service Dress, C in Polish 1919 Pattern SD and towards the end of the campaign in Japanese, Portugese, Bulgarian etc, each attempting to achieve some conformity to the regulations.
The Imperial German style uniforms tended to be worn by the forces in the west of Poland . French pattern uniforms, were , as far as possible confined to those units originating from France. ( But again not always).
As the campaign began the greatest variance was seen in the units at the front line, ( Dniestr and Dvina rivers) since they were furthest away from central supply. The units being raised in the core of Poland were starting to be uniformly supplied and showed a great conformity to the regulations. However as the Bolshevik counter-offensive drove deeper into Poland, the drive to raise new units to counter this threat and the loss of sources of supply by the withdrawing front line units, meant that the units used whatever they could as they could, and every permutation of uniform was possible.
There is no definitive answer that can be given to the question.
There are some interesting examples of the variances available.
If you type SYLWETKA ZOLNIERZA POLSKIEGO 1920 and access http://www.patria.fora you will see recreations of the different type of uniforms worn.
The first shows an officer ( appears to be a lieutenant) wearing a mixed bag of German tunic, regulation breeches and a pre 1919 cap.
The second set of photos is particularly interesting and reflective on my description of the situation. He is described as wearing an American blouse, Austro-Hungarian equipment, older style cap ( which actually was quite popular with the troops at that time) and a Berthier rifle.
In the third set he is wearing the same as in the second set, but now has the French pattern helmet ( derived from a number of sources not only France) and an Austrian pack.
The fourth repeats the previous two.
The fifth shows the American blouse etc, but worn with French equipment.
The sixth on the page shows the 1919 regulation Polish pattern uniform. The form of side cap shown was interchangeable with the square-topped ‘rogatywka’ type.
(the remainder show uniforms from 1939.)
If you access http://www.1920.org.pl , just below the heading you will see WOJNA POLSKO-BOLSZEWICKA and a sub-heading WOJSKO POLSKIE. Clicking on that will allow you to access a few original photos. ( Piechota-Infantry, Jazda-Cavalry, Artyleria-Artillery, Lacznosc-Signals).
Lastly, if you type REKONSTRUKCJA SYLWETKI WOJSKA POLSKIEGO 1920 and access the site http://www.radunin.hosit pl you will see yet another variant.
The figure is described as a Senior Private/Lance Corporal of the 10th Infantry Division. The tunic and trousers are American ( sold as surplus to the Poles in very large numbers), and have been modified locally to have a Polish pattern collar and Polish buttons. Austro-Hungarian leather equipment, pouches and entrenching tool, German pack, water-bottle and bayonet, and carries an 1989 Mauser.( If the tunic shown here is substituted for the 1919 Polish pattern given before and the cap is substituted for the square-topped one, then you get very close to the regulation pattern established and being introduced mainly towards the end of the campaign)
I hope that this gives you a general starting guide, to this otherwise complex issue. I am more than happy to try and answer any more specific questions you may have on the topic.
I must also apologise for not being able to provide you with the direct links to the sites. Unfortunately I am of an age where I still wonder that my keyboard doesn’t play music but makes words appear on the magic-lantern screen in front of me, and have a learning curve towards technology that can be rivalled by a plank of wood. I haven’t quite got to grips on how to do this but do hope to achieve this before the Sun eventually swallows the Earth.
