Not sure about engraving but give Bolsa Gunsmithing a call. Had them do some blueing for me on a OMBH and it turned out nice. Good pricing and didn't take four months. www.bolsagunsmithing.com 714-894-9100 westminister, ca I-405&bolsa ave.
Try Sean McVicker. His phone number is 619-390-7550 and his email is [email protected]. He does custom design and engraving. I've seen him at the Cross Roads of the West gun show frequently and his work is very good. Prices seem reasonable too. I've never had any work done but I've been thinking about some engraving on a Colt M1903 (or M1908) in .380.