A RC refers to the K98ks the Russians acquired during or after the war. Sometime in the 50’s or 60’s, probably in more than one
session, the Soviets in their bureaucratic wisdom decided to disassemble all those rifles, coat the parts in various goop finishes and then reassemble them with no regard to what parts were used, and used an electric pencil to “match” the parts.
So to answer your question the rifle is not original as the Germans produced it. It may still be in the condition that the Soviets put it in, but only pictures would tell. As to what stock it is supposed to have, it could be anything from a Standard model stock to a full Kriegsmodell stock. $1300 would be to much for a RC unless the barreled receiver it was built around was very rare, think SS gew.98 to K98k conversion type rare. Average range for an RC is $700 to $800.
The above is just my opinion, others may disagree.