Piedmont NC is mustard, chilli, slaw, onions. (Not some soupy mayo based crap but a light white slaw with a hint of carrot, celery salt, pinch of sugar, touch of vinegar and a wisp of mayo)
Zac’s in Burlington can go to hell. They are unc fans.
Henry James on the south side of Asheboro on old 220 had the quintessential Piedmont hotdog. Yes the steamed bun is key.
Monica’s in DC could really handle some wieners in the day. They specialized in a small brand from Arkansas but closed down in the late 90s.