While there are methods of blackening stainless, I don't know of any that can do small areas.
On idea is to have the top strap and sight area bead blasted.
This gives the stainless a dull gray color that doesn't reflect light.
This is how most gun makers treat stainless pistols to cut glare.
If you go this route, be CERTAIN that the bead blast is either one that's used ONLY for stainless or aluminum, or is filled with ALL new blast media.
A blaster setup that's been used to blast carbon steel will blast tiny particles of carbon steel into the stainless and this will rust later, damaging the stainless.
DO NOT trust anyone's word on this, make sure the cabinet is stainless OK.