Handgun coatings, plate work, treatments...
If you are looking for a high quality coating or plate work there are a few popular choices out there;
www.Bearcoat.com www.Black-T.com www.APWcogan.com www.robarguns.com .
Bearcoat comes in a few color choices & runs about $220.00 that includes return S/H,
. Black-T & Green-T are highly rated. Accurate Plate & Weaponry is a AL based firm that offers nickel, Teflon, Cerakote(NIC), & other custom choices. The site has a link to a cool chart where you can view a Glock pistol with different NIC colors; green, silver, black, blue, tan, camo, etc.
Robar Guns based in AZ is a firearms industry leader with a great service record. I suggest the black oxide or the new NP3+. They also have many options or styles but some treatments like the black RoGard are - in my opine. I had a new in box 96D pistol coated with black RoGard. The Beretta 96 got scuffs & wear marks quickly.
I'd also used a NP3 treated 96D in the 1990s with 0 problems or issues.
SIG Sauer also does "CPO" or factory service jobs on older P series firearms.
It includes new springs, barrels, sights, Nitron plate work, grips, etc. See
www.sig-sauer.com . It ran around $110.00 but the cost may have gone up.