I've got a 1960 336SC that's awfully nice, but I wouldn't say it's the best one of the bunch. I just don't know enough about them, either, to say so.
I will say that Marlin did a lot of experimenting around with the 336 during the '60s, though, and did lots of nice things, like the Marauders and Texans, to go along with the 336As and other somewhat "different" versions.
You might go over to marlinowners.com and read around over there, and maybe decide for yourself what you're most interested in buying.
There's a lot of knowledge over there, that can be tapped with a few polite questions.
Personally, Marlin has made so many 336s/30As, that I don't fear putting a swivel stud in them, or any other modifications, that seem to make those guys cringe. Crap, they are everywhere, it's not like they're rare or even in short supply, anywhere. I don't have the reverence for them that some of those folks do. Good rifles, mine is nice and kills a deer now and then, and shoots well, but it's not the Holy Grail, it's a flippin' rifle that was made by the millions.
