Quote Originally Posted by The Deil's Chiel View Post
One thing that I have noticed is that today's Regulation doublets do not button in front, or else they are held closed with two small buttons attached by a short link, the diagonal rows of three buttons on either side (as found on the Prince Charlie) seem to have replaced the three functioning buttons that used to be in the front of the Regulation doublet in examples back to the 1950's and earlier.
I don't believe the buttons on regulation doublets are intended to actually button, despite the presence of button holes on the opposite side of the jacket. Looking at a number of photos and illustrations from the period 1900-present day, I can't find a single example of the jacket closing. Just as a tails coat is intended to be worn open, so it seems that the dress Argyll, the Regulation Doublet, and the Prince Charlie coatee are also intended to be worn open.