Working in a pawn shop part time, I am familiar with this sort of thing.
True story.
Fellow comes in and has a rifle that "dates back to the Korean War" and wants it evaluated for sale. I am busy with another customer, but can overhear the conversation with one of the other guys. Basically it centers around all the parts being stamped with a serial number, similar to many military rifles, it being bolt action, and it being "odd" , as in what is not familiar in terms of military bolt action rifles (A3-03, Mausers, M44, Enfields, etc.)
The other guys are struggling with it to identify it, and I finish up with my customer and wander over to see what is going on.
I get handled the rifel and ask if I have ever seen one before. At first it gets me, too. It had been sporterized, so the stock was way down the barrel, uncommon to most military rifles. But it gets me in the back of my head.
He hands me the bolt, and the bells go off. It is a Swiss K-31.
http://www.aimsurplus.com/product.aspx?item=F3K31
They are old rifles, but they got dumped on the US surplus market about 10 odd years ago, similar to the SKS and Mosin Nagant rifles.
What the man had was a $50 rifle that some buddy of his had passed off to him as a rare and unique war bring home.