Montesa's enduro models are not that easy to work out, montesa didn't realy change to a new model year to year, they sort of just evolved. 67m is a Enduro 360cc if it has a red tank it's an early(1979) model H6, Yellow tank came along abit later, then the H7 had a white tank. Being an Enduro it should have a compliance plate on the head stem with a build date on it I would have thought.