Hello Ed and Welcome aboard The Forum,
As for your question as to whether or not to NP3-ize your R9 Stealth. . . . . . With the finish that is on that sidearm, anodized 7075 T651 Aircraft Grade Aluminum frame and the 416 Stainless Steel barrel and slide, she is fine just as she sits for the duty you require.
Anything extra, frankly and in my humble opinion, is nothing more than "Fluff". Keep her clean and oiled and use the prescribed ammunitions and you should be fine with it in your off-duty mode.
Should you have any other questions, feel free to PM me here through this forum.
Please Stay Safe out there. We really appreciate what you good cops do for us, we the people.
Respectful Regards,
Eric C. Rohrbaugh