These are a real gray area for me.
Branko refers to a number of these (gew98) being converted into "model1924b" in the 1930s (or 39-'41(?) I'd have to reread that section in detail).
I suppose it is possible this is a post war refurb of one of those?
Hopefully John Wall or others more knowledgeable nor I will pipe in with specific details.
You see frequently GEW reworks in Russian captures. Could post war Yugoslavia have accumulated these in post war reparations or battlefield pickups? They could have easily found their way into the 1948 conversion program. Just a guess.
Could be either, of course, but I'd WAG that it's a German-converted Gew98 that was captured by the Yugos in K98 configuration and put through their refurb program. Either way, it's a nice-looking gun. The YC K98's are much better looking than the RC's.