I have a question for the experts out there. I am fascinated by this picture (as with most of the portraits from that collection):




My interest here is on the fellow at the right side of the picture. He's wearing the Colquhoun tartan, which is why he caught my eye. I notice that he's got a basket hilt sword and what looks to be a targe on his left arm. The rest of his wardrobe seems to be military style stuff as well. Aside from the weapons, would this have been limited to men in military service, or was it common to see men dressed like this in civilian life?

But the real question I have is what kind of hat is he wearing? It's not a Balmoral, Glengarry, Tam O'Shanter, or anything else I'm familiar with. Is it strictly a military piece of headgear, or would this have been commonly seen as well?