So that means new uniforms?
Nope, devs already said that for now they will use Soviet models with eagles on helmets. To be honest I don't know how widely issued were Polish pattern uniforms by the time of Battle of Lenino. Unfourtunately I don't have a book on a subject. I have only one about Polish uniforms from 1918-1939...
On photos taken during 1st Inf Div military oath on july 1943 (three months before the battle) soldiers have mostly polish uniforms. There are not a lot of photos from battle itself though
Here's a photo from July '43
But here's a photo of Polish soldiers transported to the front and you can see a mix of Polish and Soviet military uniforms (note the collars).
So to summarise, retextured Soviet models will do for now, but for any later battles of LWP from 1944 new models will be needed.