I do the usual tune up of the newer, MIM internal parts.
The rebound slide is coated with what looks Teflon, and I don't get carried away stoning that. Anything that slides or rubs gets stoned.

I've asked the question elsewhere; anyone know if the hardness of MIM parts is surface only, or homogeneous?

The only part that really makes me uneasy is the sear engagement on the trigger. The drill is to sharpen that to eliminate creep, dull it to lighten break.
Caution is the rule, but is there a difference in hardness/durability to the MIM parts?
Thanks in advance,
Moon