There may be a square on the barrel that has two letters in it, the first will be an "A"(at least in mine) the second letter indicates the year it was made. Mine was made in the 1980's and has "AN" in the square. I am sure that someone has that list of letters and the dates that go with them.
I like my .50 cal. Investarm Hawken better then the T/C model. It has better wood and is finished very well.