42mm cap on the Canon 50mm f/1.5 LTM (40mm filter thread)
50mm cap on the Canon 135mm f/3.5 LTM (48mm filter thread)
60mm cap on the Canon 85mm f/1.5 LTM (58mm filter thread)
Still missing the 36mm cap.......
And here is a reference for the two typography on the cap that Peter Kitchingman referenced in his blog article.
Late type. Note that the letter "a" is now a flat top.
To be honest, I would not use these caps. Quite a hassle and it does not allow me to use the slim filters that I am very fond of.