Someone commented on some problems with teh formal silver buttons having very long shanks and thus not lying flat when sewn onto the outside of the jacket. Many of the original buttons designed for formal kilt jackets are designed to be removable so that they are off the coat and out of the way when the coat is formally cleaned. to do this they must have a long shank, have that shank put through an actual hole in the jacket, then affixed inside the jacket with some form of pin, like a small cotter pin. The pin ca be removed to remove the button for cleaning. My Argyll and waistcoat are made this way, so I have to remember to manually remove the buttons before sending it off to the cleaners, then take a couple minutes to replace them upon its return.

My understanding is that this is the practice in the UK where a large percentage of the kilt jackets are rentals and need to be frequently cleaned without risk of damaging the expensive shiny buttons.