Re: pre/post 64 winnie
I do believe that the main differences is that the Pre '64 receiver steel is supposed to be stronger, and that the bolt has a 3rd tang on it that engages the rear section of the action. I'm not 100% sure but I think they are all controlled round feed/claw extractor as well.
If it is a newer model, like my 300WM - it is listed as "pre-64 style action". This only means that it is a controlled round feed/claw extractor.
I keep nature balanced - I hunt everything!