Malcolm long is an engraver near me, he is very well known and has done Holland and Holland's and resto work, but i have no idea what the going rate is.
I have a Calderwood double percussion gun that i am restoring with lovely elegant barrels nice wide rib and its signed "Dublin." on the rib ( calderwoods on the locks ) Just dublin on the rib alone just looks so striking and makes such a statement on the gun as its in old script style it needs to be done.
I have a back action sidelock non ejector by Slingsby of Boston Linconshire, the name is fading just on the rib due to re browning, and because i particularly like local provincial makers i wouldn't mind having that picked out as its going to be restocked soon.
I am with you on that if its really worn throughout there is no point, i have one that is very worn but the locks are not signed, so the only signature is on the top rib but that will disappear when re browned. The gun was a quality piece and the barrels will come up nice so i want to make sure the gun is attributed to the maker.
The thing is without knowing what the going rate is i would not even know what to begin to pay.