just found this link online which says
"First model of Icarex 35 is based on the earlier Voigtländer design and was launched in 1966 through the collaboration between Voigtländer and Zeiss-Ikon. Icarex 35 S series, like this was introduced in 1968. Two variants BM (bayonet mount) and since 1970 TM (thread mount) were made."
so i will have to measure for sure does anyone have any pics of what the BM (bayonet mount) looks like?
i just found this link aswell
http://www.camerapedia.org/wiki/Icarex
"The special bayonet mount and the limited range of lenses were hampering the Icarex sales, so the two models were released in a modified version accepting 42mm screw lenses. They had a TM badge to distinguish them from the bayonet versions, that remained in production with a BM badge. An Icarex with no BM or TM badge is a bayonet body made before the thread mount version was introduced. "
so it looks like it is going to say it right on the lens.