I had a alloy suzuki option swing arm on my bike in late 77 i also had a full floating rear brake that was hand made by my old man ,Probably from the picture on the frunt of the RM service book which shows them on a 250 A model, We got the on we had from a road racer who had had it most of the year.The welding on it is not a tidy as a C model one.So if it was on my bike ,and i have that bike in my shed then all I need is sworn letters from fellow compeditors from that era, the RM parts books, a letter from the pope that i attend church each Sunday and Im sweet right ?