My '66 Lightning needed one but it looks like someone welded on the frame mount backwards! I had to do some grinding to fit a stand like the one above. Thing is it was somehow too long and wouldn't go up or down without tilting the bike way over to the right.
I bought a shorter one on Ebay advertised as "Triumph BSA stand 83-1605 ".
More grinding, etc. but works better for my situation.