[LMH]

Having competed in concourses with a Porsche in the 80's and early 90's, I don't see the issue here. Unlike a car show, a concourse is a competition on how close to original an original is. A replica would not be able to be competitive as it was never produced by the original factory, whatever make that would be. Points are deducted for repaint, new upholstery, missing tools ( I used to get dinged on that one) etc. So a replica would have no chance and the judges wouldn't be interested in judging it anyway.
Cars put for display only weren't judged, so they weren't in the same area as cars that were.
I think that's how it should be.
Larry