I recently acquired one of the "by His Majesty's Letters Patent" mandolins, unfortunately the back was already half off:
So it was time to take it off completely and see what's inside - fairly typical bracing on top and back - top is 3mm spruce, back is 3mm slab cut maple (one piece), sides are 1.5mm curly maple (too thin IMO - they're collapsing somewhat):
A few interesting / strange points: there's a metal fixture on the main cross brace (appears to be original):
No idea what that is for unless it's a weight?!?!?
There are also some reinforcement patches on the top, plus two holes directly under the bridge (which actually miss the reinforcement plates!), again I can't really imagine why these were put in there:
What these are all about of course is the picture on the back:
This appears to be printed/transferred on after the finish was applied - which I guess explains why these tend to be in rather shabby condition Plus I've seen these both with and without the image, so I guess they just finished them all the same, and then applied the image to a select few afterwards.
Anyway lots to do on this one, and I've always wondered what these were like, so it'll be interesting to find out.... I'll just have to resist the temptation to try and make it "better"