Not to argue about whether or not ops actually installed them BITD or not, but of the half dozen or so DK's I've been through, all but one had them. As well as 2 cocktails and a cabaret. Which has little bearing on BITD, but does follow factory specs. I can see them being broken off and destroyed by the teens of the day, so heavy use machines surely eventually lacked them.
Now it is completely an aesthetic preference.
As for scratching, if the cpo and the bottom surface of the cover were buffed smooth and burr-free, they should only scratch if foreign material built up under them - which in a home-use environment, would be next to nil. If you cared about that sort of thing, which I personally don't.