The Mosins are what showed up at the end of the milsurp "golden years". Prior to that, you could find very nice Mausers, Ariskas, K31s, Springfield '03s, etc. at really cheap prices. A lot of people (myself included) bought them as investments. Most of mine sit in the safe and I only shoot a few of them. As can be seen in the K31 thread here, they can be a pretty nice investment vehicle. Nevermind the markings or any "collector value" characteristics of any of my German Mausers - I could sell the forged actions on most of them today for double what I paid for the rifles.
I also enjoyed buying some of the Mausers that weren't really for investment, like the Turks, and breaking them down and rebuilding them and refinishing the wood on them. It was a fun hobby and learning experience for me, and if I screwed up a $50 rifle while learning, no big deal.
I didn't get my C&R just for milsurps. I fully wanted to take advantage of it for 50+ year American guns, like older lever actions, Savage 311s, etc. to buy and shoot. What I found though, was that I never ran across any "C&R FFL pricing" on them. I could just as easily have bought them at the same price sans C&R FFL. Certainly part of that may have been my living in CA, as a lot of the online brokers selling those types of guns would only ship them to a Class 1 FFL, which would have incurred additional charges to me. Pretty much all the milsurp brokers shipped to your front door.