Chris,

The Model 70 you are asking about was not manufactured by “Winchester”, instead, it was the U.S. Repeating Arms Company. To the best of my knowledge, they did not release any production information before (or after) they permanently shut down in March of 2006. You might be able to get assistance by contacting the Customer Support here – http://www.winchesterguns.com/support/contact.html

Bert