This was the info he shared with me...which ultimately led me to purchase it from him:
After lots of research, I decided to buy a 1937 model because Germany wasn't at war yet in 1937 so the wood was a nice walnut (expensive) and the gun was made with much higher tolerances / quality than the ones made when the war broke out. After the war, Russia took almost all of Germany's Mauser K98s and shipped them back to be stored, so if they ever went to war with the USA, they would have about 10 million rifles ready to go. As a result, any K98 that you buy now will have a thick nasty coating of red cosmoline all over the gun to protect it as it lay in storage. I had that all removed, professionally cleaned and the stock was just recently re-sealed with tung oil. I have also added a cleaning rod and a leather sling. It's a great shooter and lots of fun, especially since ammo is so cheap. Every time I shoot my K98 at the local rifle range, people always put down their AR-15 or Ak47 and come over and ask to shoot her. It's a really awesome gun to have.
The gun, leather sling, plus one stripper clip of 5 rounds of 8mm ammo all for $275. Most K98's you find online will not be de-greased, will not include the sling and cleaning rod. There is absolutely nothing wrong with this K98. The headspace has been checked by a gunsmith and was found to be perfect. This is a great shooter.
There are 3 Waffenamt armory stamps and 2 Weimar eagles clearly visible on the bolt and the housing. There are no swastikas or Waffen SS marks on it since the Nazi's didn't start that until the 40's. I like that because you can show this gun to someone and not feel like they might be offended.
My friend showed up about an hour ago and let me tell you, internets...this thing is beautiful. I don't think I've held a prettier rifle. It's clean, it's solid, and it's about 80% original...numbers match on most of it. No rust, pitting, or throat erosion. Bore is shiny and beautiful. I took the bolt out and checked it meself - utterly beautiful and clean. Did i mention it's clean? :D
Anyway, I'm tickled to bits with this rifle. I've always wanted a Mauser, and this one literally dropped in my lap. No more gun purchases for me for awhile, I think...I'm going to savor this beauty for awhile. My partner played with it once he got home, and said it's one of the better rifles he's seen...the metal isn't marred in any way, and the wood is in great shape. It's obvious it was used, but nowhere near the amount a 1940 would have been used.
And of course, I can't end this without pictures (click to embiggen):
Yes...I'm happy. I don't think I've been this giddy about gun shopping/buying since I bought my pistol. I can't wait to shoot it!!