All you need to remember is that if the .243 came out in 1955 that the gun cannot be older then that.
Add to that if it says Chicopee Falls that is had to be made before 1960.
That puts it in a 5 year time frame.
You can contact the Savage owners club and have them date code the barrel and serial number if you want - but my guess is that your rifle is going to go down the road sometime soon when the selling price gets high enough.
People always say that they are going to hang on to it.
Only to change their mind when the newest, latest and greatest gun comes along and a have to have scope and the old gun goes bye bye quicker then a fire cracker on the 5th of July.
These young kids are all brain washed by gun writers and public opinion that screams that you need maximum velocity and magnum power and a light weight gun to boot.
The .243 was a awesome varmit gun - but never really intended as a deer gun.