I sent a total of 4 SBRs for engraving, one was a CZ scorpion which has polymer frame, no problem at all, nice and clean engraving and a very short turnaround time, I shipped from Raleigh and got them back within a week or so every time, job well done.
I bought a B&T GHM9 from Tarheel a little over a month ago, and couldn't be happier.
Didn't feel like making the ~3 hour drive so I had it shipped. He easily had the best price on it, and engraved it free of charge. I expected the engraving to take a day or so, but it was shipped within a couple hours of ordering. Almost took me that long to find where he hid the engraving. 🤣