If the dating is correct, its a Winchester Model 70 push feed rifle which were pretty good rifles back then. Later New Haven rifles built in maybe the last five years there were sketchy at best on occasion. Disgruntled union workers weren't always conscientious workers.....
Some prefer the CRF Model 70 rifles (both pre-64 and later New Haven USRAC rifles as well as today's Model 70 rifles), but that is a ford/chevy thing for shooters who never go after man eating animals. Probably the best feature of the CRF rifles was/is the larger claw extractor when compared to the push feed tab extractor. Even today its still a debatable issue among Model 70 hunters and shooters largely based on their own perceived needs. Personally I like the CRF rifles best, "just because", but when hunting white tail its a total non-issue. And most of the push feed Model 70 rifles shoot very well.
7x57 rifles were not a rarity back then but they were definitely not produced in the numbers you'd see for a 270 or a 30-06 for example. They were fairly common and readily available if you were willing to look, but due to consumer demand, not every small mom and pop gun shop would stock them when they could sell a better known rifle caliber to anyone walking in the door. Utilizing PT Barnum's theory, some Gun Broker, etc. internet sellers use lots of hyperbole to sell what they have.
All in all, the 7x57 is an excellent cartridge, albeit a bit under powered for what Mr. Bell did to elephants with it. But he wasn't a typical week-end hunter either. For NA game up through elk it is a very good choice even today. Either of the two powders mentioned plus 140 grain bullets should work well in OK.