Very common for parts to have one serial scratched out and another stamped, especially Warsaw Pact nations. Pretty common with 91/30's etc. When they went through a rebuild, a lot of times they just put parts in a bin, refinished everything and put them back together as a new rifle. The East Germans apparently were a bit more selective and only rebuilt or replaced things that actually needed it. Thus mostly matching parts and the occasional replacement.

I'm no expert on K98icon's but from what I can see there are two basic types. The all matching GI bring back and the non-matching captured or re-purposed rifles coming out of Eastern Europe. Values of the latter seem to be more dependent on where and when it was made and the rarity and amount of matching parts but these days $400 is a good starting point for a very basic Russianicon Capture with mis-matched parts. Based on condition and appearance, yours would probably bring something north of that. There are a few guys that say anyone paying $400 for an RC is nuts but I'd like them to show the rest of us who is still selling them for less than that. A lot of guys out there willing to pay it. I think I paid about $200 for mine but that was 4 or 5 years ago and we can't live in the past forever. It's getting so bad that re-enactors are using Yugoicon M48's and in turn driving those prices up.