I was once told many of the early T/C barrels, before they made them themselves, were Sharon barrels. I had a friend that owned one of the early T/C rifles. He was sure he had a Sharon barrel and it was a 1-66 twist. It sure was a round ball shooter. As for determination of the age, I would think T/C could tell you by the serial number but then you never know.

The early CVA had Douglas barrels on some of their Mountain Rifles. Those that owned them held onto them. They were great shooters.

Sounds like you have a great rifle there.