As you probably know, 1970 would be a Type 2 or possibly Pre Type 2 barrel (the generation of barrels where the most different chamber's were offered by TC).
The exact offerings by year I doubt are listed anywhere that you can just access on-line. And details are sketchy at best from the early years at TC before their first catalog in 1974. Brochures and printed ads were used before it, but few of them survived (I have one ad from 1967). While I got my first Contender in 1968 (38 Special), had them all since and have some old TC literature & catalogs, I can't give you an exact answer for 1970.
Your best bet is going to be to contact the TCA, someone like Ed Kirkpatrick or Ron Sable for the most accurate answer.