Anyone know what the three plumes on the gold oval inlay in the stock may signify?
The three plumes are generally taken as being "The Prince of Wales' Feathers", an heraldic device that goes back to the thirteenth century (or before for all I know) being the badge and symbol of the Princes down the ages.
There's many a pub called the Prince of Wales, or The Prince of Wales Feathers and they usually carry a pic of the device on the pub sign, as below. I believe the true emblem has to be of three ostrich feathers within a coronet bearing the legend "Ich Dien" meaning "I serve".
As to why they appear on the escutcheon of your gun I don't know, but the Lascelles were as you say, close to the Royal family (and are now related by marriage) so it might possibly be a presentation piece. Sometimes companies are appointed as "Suppliers of Guns / underpants/ door knockers" or whatever to members of the Royal family. I suppose it might just be the Boss were Appointed and popped the symbol on.
Eug
