Check with GRS in Emporia Kansas. They manufacture the actual tools for this type of engraving. They have several samples in their catalog of work done on guns, etc. I'll bet they have someone who is the best they know who will do this for you. Below is their web address. Bill Janney, who carves gunstocks and is pretty big in the woodcarving world also does engraving. He gives seminars there. They have a pretty awesome gallery you can look at on this site. I bet living in North Oklahoma, Emporia KS is probably 4-5 hours away is all.
http://www.grstools.com/