No Freaky, it would have to be a Profab part that was for sale in earlier than Dec 31st 1974. For example a Profab swing arm built for a 1976 TT500 would not be legal for use on a 74 yamaha or something else not that anyone would try to i dont think, but i was just trying to make an example. if Profab built it before 1975 and you could buy one at your local shop before 75 then you can use it in Pre 75 as long as you can prove it was available then.