The age is probably just what you say: early '60s. The buckstitching on that tab thing behind the seat was '60s and into the '70s, before dark oil took over in early '70s.
The conchos and horn cap are probably nickel (German silver).
The saddle is modern-looking enough that it would probably fetch about the same as most modern roper saddles that are mid-oil color like that. The double skirts make it look modern as does the mid-oil color. fortunately that that little bit of buckstitching is up there where it won't be seen from the ground. A 16" seat would be a good thing, too.
Take a lok at TackTrader, equinenow.com, Horseclicks and see what similar looking saddles sell for. Teskly's used saddles, too, but they are higher than private sale prices would be. I'm thinking maybe $600-$850 but I don't track prices of older western saddles except the show saddles with sterling silver.