Hello, I purchased this Mosin in 1989 for $50.00. I believe it to be a Finish M28, it has a SIG 28” bbl, it does have a splined stock but seems to have a M39 rear sling swivel, it is a Civil Guard stamped, has been stamped with the D for ammo and has been counter bored. The rear sight has been remarked and is not adjustable for windage. It has dog eared front sight (tap adj) and an old style bolt handle as well as trigger. I am unable to determine a date of manufacture. The original serial number seems to have been crossed out most likely when the civil guard unit number was applied. There are many various markings that I could not find in your guide. I have about 10 packages of original paper wrapped 7.62x54R ammo left and have shot a few packages through it. It has a leather sling which looks original but I had to replace the dog collar sling loop. Original serial number seemed to be o16078 and SY # is s107363 which matches the bolt. I have photos of more markings.