The engraving and inlay looks very much like the work of Alvin White, but the work is attributed to a firm in Germany.
No matter, it is beautiful to see and thank you for posting the links.
The owner asked me to examine and comment on those revolvers at the 2016 NRA convention in Louisville, KY. They were engraved through the German firm, Friedrich Wilhelm Heym, however I was unable to identify the specific engraver. The work is reminiscent of Claus Willig or the late Erich Boessler. In any case they are beautifully done though much of the value lies in the Elvis provenance.