Non-regulation M43 Jacket?

[Al-muell]

Got this one recently at a low price. At first it looks like a very dirty m43 kitel tunic, just without shoulderboards and with buttons moved a bit to widen it.
The buttons look good (one is a replacement and it seems to be from 50's - can't read the date on the back, but it's later 2-piece brass one), the material seems to be light-weight wool (cheviot). But the problem is that the jacket has no piping around the collar and cuffs - and not even a trace of it ever being present there. I thought it may be an earlier (m35/m40) jacket re-made to look like m43, but those had sewn-on pockets, I think.
So what is it? A re-made non-military uniform? A custom-made jacket?

[toshik]

It's a civil version popular before and after WW2 in USSR - same exact as military but without piping and insignia (shoulder boards or collar tabs on pre-1943 uniforms).
FUI M35 had piping.

[Al-muell]

So, the army buttons were addedby the seller most likely?
What buttons were normal for this jacket? Standard 4-hole?
I would replace the buttons with proper ones and find a better use for these here.