I have a few handguns and one of my oldest is my PT 99.  Ive shot thousands of rounds through this and it is extremely accurate and reliable..  I know the brand’s reputation has gotten tarnished by more recent models as well as poor customer service.  After about 10,000 rounds I replaced the barrel and recoil spring.  Now I’d like to replace the sights with other adjustable sights.  Hopefully large enough for my old eyes to focus.  Customer service is no help.    Ideally I’d like to have it milled for a red dot.  Please don’t knock my taste in pistols.  I also have a G 17.5 G19.3 and a Cz Shadow 2.  Can anyone provide me with a name for milling or a place to by sights.

I imagine Langdon Tactical will do it. They do it for Berettas.

https://www.langdontactical.com/custom-gun-work-ltt-rdo-elite-optic-cut-for-your-92-slide/

You might check with AmerigunUSA