I have a Sears model 53 that my grandpa bought maybe 38 or so years ago (when my dad was about 7 years old). I have determined that it is a Winchester model 70 with the Sears name on it. Are there ways to tell if it is a Pre-64? If so, what are the differences, and why are so many references made to this peticular year? What changes were made in 1964? Just curious, it comes up a lot and I would like to know the difference. Either way I will NEVER get rid of this gun, just want to know. Thanks guys.