Yes, no problem. Both are permanently screwed onto the back of my M6 (.72). Dioptre is -2. I do not use wider than 35mm.
One note of caution. Over the last few years I have lost two dioptre lenses because they unscrewed. This could get expensive. I have put a tiny drop of 'Locktite' on the threads to stop it happening again, ditto with the magnifier.
Michael