By the serial number.
The last model 70 in 1963 was #581471. 1964 started with #700000.
Serial number.
No, it was not.
No the model 70 Winchester made before 1964 was never made in stainless steel.
I don't have the Fjestad book with me, but I can tell you that it's after 1964, probably in the 1968-1969. Definitely not a pre 64 model.
the model number and serial number will give you the information,then ask your question here and you should be able to determine if your Winchester is a pre-64.
The serial number. If the serial is less than 2,700,000, it is a pre-1964 gun.
Buy the serial number.If your Winchester model 70 rifle has a serial number lower than 581,470,then it was made prior to the manufacturing changes in 1964.
Proofhouse.com has sn data The serial number will tell you the date of manufacture. Go to this site: http://armscollectors.com/sn/windates.htm
Is the serial number less than 581000?
pre '64 is based on serial numbers under 579600