20 guage D. Murray shotgun

Hi. Looking for info. Friend has a 20 gauge double barrel shotgun. Has markings (crown with something, crown with BP, crown with BV), see pics, but no serial number. Has D. Murray engraved on each side. Has D. Murray Brechin on top between the barels. Initially it was thought that it was a personalized shotgun with owners name and initial. However, we were able to find some information about a Scottish gunmaker from early 1900s in an archived gunsmith magazine.  Gunmaker was called D. Murray, but we were unable to get more info and to verify that this shotgun is in fact from said gunmaker etc. Can anyone shed any light on the matter, or advise where to turn for info. We are interested in finding out what it is and how much it is worth. Can't seem to upload higher resolution pictures for some reason....but would be happy to send pics via text or e-mail if anyone wants better quality pics, just don't know how to on here. Thx everyone.