The kilt is presumably a modern tailored kilt with 8 yards, though we can't see the back. That would mean only 130 years or so of history to reccomend it. I'm not sure that vests like that were ever worn with the kilt, honestly, and that shirt is also a modern innovation with no history behind it.

So in short, Jock was kind in saying that the look "is not really anything that historians would recognise". For my part, I'd call it a marketing ploy.