The two deep, relatively equal sized holes certainly point towards it beginning it's life as an actual Albanian 561 replacement stock that was then cut down for a Chinese SKS HN. The stock in the middle is a Alby replacement stock made specifically for a blade bayonet Chinese SKS, while the other two are Albanian 561 stocks with spike bayonets:
This image shows what is under the buttplate of true serialized Alby stocks on Albanian SKS 561's:
And this image is two more Sino-Banian SKSs with the same configuration as yours. Only one spring in the cleaning kit cavities seems to be the norm:
I've never noticed that the two holes are different sizes, but that may certainly be the case and it may be the case that the springs are different sizes. That one of those thing I'll have to check next time I have a buttplate off an Alby
.
The springs that go in the holes are tapered, meaning that the base is wider than the top. To insert them, you have to kind of 'wind' them in. This keeps the spring captive in the hole without any kind of retainer and prevents the spring from coming out when the oil bottle/cleaning kit is removed from either of the buttplate trap doors.
There also *may* be indications of 'the divot' right behind your sling swivel. Hard to really tell and from the prep before finish, application of the finish, and subsequent abuse, it kind of looks just like any other dent, but it's in the right spot.