Interesting story, I had one also that was my Dad's (I think he bought it in the early 60's, he was a GI and bought it from the Base Exchange in those days) that rifle was stolen from me in the late seventies along with a Win model 770 in .270. I had serial numbers of both firearms and included them on the police report, I received a phone call from a Detective from the San Antonio PD 6 or 7 years later that an honest pawn broker ran the numbers on the Win Model 770 and called it in. I got that rifle back but never the Model 61 Gallery Pump .22; I can't tell you how many gun shows I've been through and, gun shops around the country I've been in over the years and have found a few for sale but most of them were pretty wore out or ill treated. I have found a couple over the last few years in fine condition that were from $950 $1400. In my estimation is that the rifle for $750 in good shape is a fair deal, you might latch on it and you might want to later pick up one in better condition if you found one, I can't believe you'd lose money on the $750 rifle. I think folks are holding on to them if they have on in really nice condition, they are really neat rifles. You might imagine, I always look at the serial # when I do find one and get a funniest looks, usually get asked why the numbers were important, like there was a bad run of them made or something that they didn't know about them.
Best of luck Amigo!
Bret