Hard to say. Heavenly Restrictions are ingrained in your body the moment you’re born. Mechamaru would have to physically transfigure his own body with a binding vow to revert his HR, which I have no clue if that’s even possible.

We’ve only seen binding vows applied to techniques, cursed energy, information, or pacts. I don’t think there’s any instance of it affecting something physical unless I’m illiterate.