Looks like a pretty bog standard Russian Captured (RC) K98k.
The Soviets had some pretty significant stockpiles of captured guns after the war, and sometime between then and now they tore them down into their constituent parts, threw out the worn out or broken bits, and re-built working guns out of what remained. Usually zero matching parts. Many (but not all) RC guns have a X mark stamped on the receiver that denotes being a captured weapon. Fewer (again not all) will have the swastikas defaced. The vast majority (again, but not all - my personal hypothesis is that this was a multi-step process and this happened years later) will have the gun refinished with that black finish you see in your pictures, and the stock covered in a thin shellac. Many times (but not always) the bolt was renumbered to match the receiver. Sometimes with an electro pencil, sometimes by having the old number ground off and re-stamped. Looks like yours had the original SN ground off but nothing stamped over. Most of the time (but not always - seeing a pattern?) the stock was numbered to match the gun, as you see on the left side of your stock.
Why go to all this work? The Soviets kept them around as third line weapons. Think the kind of thing you'd hand out on street corners in case of a Barbarossa 2.0: NATO Boogaloo in the 1950s. They were stuck in grease and put into long term storage, which is how they were received by importers in the 90s and 00s. They also gave a bunch of them out as foreign aid. A fair few were captured in Vietnam, for example.
They're not considered as collectable as an original, wartime condition K98k but they are honest rifles with very real history. Personally, I like them. I think they're great starter guns because they avoid a lot of the pitfalls and outright fraud that you can find in more collectable guns. They also tend to make pretty decent shooters, likely because having a shot out barrel was enough to get the receiver tossed during the refurb processes. My favorite shooter is an RC 98k that I use for load development and general screwing around at the range.
edit: oh and the Russians tossed things like the rear sight pin and the front sight. You barrel originally had a front sight, that's what the grooves cut on the side of the FSB are for.