Welcome to the forum.
You probably need to post a few clearer pics for most to be able to determine much on the rifle.
Reads like the rifle is a Russian capture, based on the red shellac, pending photos that can be seen. Have never heard of Yugo captures. I believe they got a pile of 98s from the Russians after the war though.
Others might chime in, but to be of more help I'd need to know what the receiver ring is marked.
Are the matching numbers stamped or engraved? Stock number on the toe, side of the stock, or in the barrel channel? No WWII 98 rifles were electric penciled nor were stock numbers on the side of the stock.
The eagle/18 and 63 are the parts acceptance stamps from military inspectors who were assigned their respective areas along with their inspector number.
E/18 is normally attributed to Gustloff as well as early 'DOU' - Bruno- Bystrica rifles. The E/63 is associated with Czech produced rifles as well.
The majority of 98 stocks prior to 1945 were stained prior to final finish.
Round up a camera now, JT