This is quite a complex subject as there are 4 models floating around from '66 onwards for the Trophy/Tiger. All UK or "Home Market" models were also exported, but not to the US, and are stamped TR6 or TR6P (police models). US models are TR6R(road) or TR6C(competition). Engine/frame numbers DU 68364-DUDU85903
1968 TR6 4 gallon
1968TR6R tank 3.5 gallon
1968 TR6C 2.3 gallon.
TR6 has painted steel mudguards and long resonator silencers. UK rear light.
TR6R has painted steel mudguards and short silencers, US rear light, reflector pods under front of tank.
TR6C has stainless guards high pipes on the left side and short silencers US rear light reflector pods under front of tank .
There are other differences, but I'm off to watch the telly!!!