My friend is from Poland and was a archaeologist/historian. The only information that was passed to me is that they are Officer boots worn in combat by a relative. The left boot has what looks like blood stains on the interior. I don't know what size they are. My guess is a USA size 9 or 10 men's.
I'm sure the numbers on the boots have the size, I'm just not familiar with them. The boots are about 18" high, and heel to toe is 11 7/8".Please feel free to ask questions and request specific photos.