Heres a couple observations;
#1
the barreled action was obviously accepted into Russian service, with the acceptance marks that are stuck into it, so that baby went to Russia at one time.
Russian and Finn refurbs are usually "Scrubbed" and the double eagle was mlled or peend off, as both Soviet Russia and Finnland broke away from/overthrew the Imperial govornment.
Most European captures/purchased captures have a "capture mark" like Pinecones, Bears, "W" , "AZF" "SA" and the like....not all, but most.
The barreld action made it into the US prior to 1968, as it lacks import marks.
#2
The stock, being a 91/30 stock, was made no earlier than 1931, when M-91/30 varients when the Soviets brought them into production.
The Soviets were the only manufacturers of 91/30's.
Besides the Soviets, there were only two other countrys that got ahold of 91/30's before WWII, and your screw in sling estucions show its a pre 1941 stock.
The Finns rehabbled thousands, with Tikka providing barrels if the original was replaced.A Triangle with a "T" and a Finn spliced stock was a rehab feature aswell, as just being marked "SA" and used as is, so theres many varialtions along that line.
As well, the Finns bought 91/30's from the Germans during the Contenuation War, when the Germans join'd Finnland in their war against Russia.
The Soviets "Gave" the Spanish boatloads of both M91 and M91/30's, and the went onto "lose" quite a few thousand to the Finn's in the Winter war, those two countrys being the only ones outside of the Soviet Union that obtained 91/30's that could have donated the stock.
Both Spain and Finnland added sling swivils into the existing slots, but the Finns were made to a manufactured Pattern, the Spanish were rather Adhoc.
In the 50's The Spanish dump all their Mosins, and carried on manufacturing their Mausers and 8mm ammo. The Finns dumped their surplus Rifles in the 50's, but because they were "restricted" by the Soviets after the War in army size, and ammounts of rifles, cannon, and such, so they sold Interarms the cast offs, keeping the "Good ones
"
Sometime, and we wish we knew "when" the 91 was restocked into a 91/30 stock, most likely as an expediant repair.
How this came to be, where and when, we will never know.
150$ for such is very reasonable, as its a mismatch, unknown, and would never get past "Hobbled together". The Remington manufacture is what floats it up above 100$
Hows the bore?