Name that Lens Mount?

Copied across from my main journal:
Free to a good home at my other camera club - I thought this might be Pentax K but it does not look the same as my old Pentax Lenses.

It is a 70-210mm zoom max aperture f3.8, 
Printed on the front lens cap CIMKO MT series.
Looks to be in ok condition although that fungus is inside the rear element.