Paul,

this is correct. There have been several revisions of the Componon-S 5.6/135 and the newer ones do have a M50 mount. And both sizes are standard sizes (you will find M42 mounts on other lenses, too). You should be able to get a Lensmount with a 42mm hole. Adaptors are usually much harder to find.

Regards,
Thilo Schmid