Sadly, when a military rifle has been "sporterized" (Converted over to a civilian hunting rifle profile) about 95% of any value as a COLLECTOR'S firearm just went away, like the dew before the morning sun. What is left is the value as a light sporter shooter- Probably $100-$200, depending.
WHY did people do that? Well, long ago, in a galaxy far, far away- right after WW 2, there was a shortage of civilian rifles- and they were PRICY. And there were all of these really inexpensive military surplus rifles- they had 55 gallon DRUMS of them down at the surplus store- for $10-$15, go pick out a Mauser, add a scope, reshape stock, maybe go to a better trigger....
With the final result is pristine specimens in their original military configuration are downright scarce and pricy, but not so converted military arms.