[Feldscher]

Jaz5833,
that's a very interesting rifle you got there.
It seems to me that the stock is not native to this rifle. The repair cut on the left side looks like standart post top PE mount repair.
Plugged mounting holes are the most interesting part of this rifle. They dont fit any commonly known type of mount used on Mosins. However, there are at least five rifles with this type of mount holes. Two on Ted's site (both 1934):
http://www.7.62x54r.net/MosinID/MosinFeatures.htm
(at the bottom of the page, under "unknown side rail mount").
Spur0701 has one,
I have one as well (1928 ex-dragoon)
and now you.
The screw holes are 5.0mm (VS 6.0mm on PU and PEM) and 62mm a part.
I am not 100% sure, but I would say that it used to be one of early NKVD snipers with German GeCo mounts.

 

[Feldscher]

Jaz5833,
I just measured my rifle.
It is 61.5mm center to center for M5 plugged holes. There is no pin hole in the center and I can't check for a weld mark without removing the stock. However, there is a pin weld mark about 15mm forward from the front screw hole. It is not drilled all the way through. You should have one of those as well.

*****
Alb87, to make it simple, NKVD is a pre-war name for KGB.

 

[Feldscher]

I found some pictures that I put together for previous possible ex-GeCo thread on old boards.
*******
Jaz5833,
I would not (and will not in my case) try to restore this rifle. Just keep it as is.

 

[Feldscher]

IIRC, Spur0701's rifle was dated 1942 with 1934 tang date and no "cn"/"CH" on it.

 

[Feldscher]

... Anyone have any idea of the rarity (numbers known)?

IIRC, 500 GeCo sets were ordered by USSR. Only part of this order was filled.