Wait, so there's no (usable) key way in the momentary switches?
The
one switch where the orientation actually matters... the irony.
Most of the lab test equipment I used to calibrate had (and used) the keyway to prevent hardware from turning and to ensure it was oriented correctly. The chassis was purposely milled to accommodate.
They also put the nylon washer on the inside and the star washer on the outside, where they were originally intended. Not only does it add something soft for the inner nut to "bite" into, it also offers some protection from outside moisture.