Maybe I should have it done by a pro triumph resto guy?
GP is right on the moneyThat bike is a "bitsa" built from several (many?) different years.
All that is important is the engine and frame numbers, to make sure you order the right parts for each of those two very important assemblies.
Beyond that, you have stumbled upon one of the greatest aspects of Triumph big twin ownership - parts can be easily swapped and successfully fitted between (believe it or not) early 50s to mid 80s.