Here's an "as-found" photo of a mid-50s R.O. Harrison bike with the same fixture for the shifter, outfitted, I believe, with Campagnolo Gran Sport kit:
from a post hereabouts a few years ago:
https://www.bikeforums.net/classic-v...eam-about.html
I think that clears up that having the stop and cable guide plate done as part of the braze-on, and painted, is actually "a thing" and not a refinisher's mistake. It seems to me that it's highly unlikely this bike was refinished, because it has the flamboyant paint job and striping that are authentic Harrison features -- though it does lack standard ROH decals on down and seat tubes.
There's more to that story:
https://www.bikeforums.net/classic-v...-complete.html