It should be fine. We haven't seen a single Torque motor damaged by intake of dust, etc. There is a piece of FR-4 on the backside of the mounting holes which covers the back of the holes (it was originally placed there to prevent people from damaging the windings with long screws.
Brillaint idea, IMO. I killed a Tekno Neu by not double checking my mounting screws. $105 mistake, that was
All I ever wanted was an honest weeks pay for an honest days work.