If a dog can do Welch Dickey they can do the ledges on Baldface. The ledges are mostly a series of large granite steps. Its is more exposed than welch dickey ledges as the steps are narrower and the terrain steeper. There is the specific trail route and lots of potential work arounds, my guess is typical unleashed dog will just find work arounds. That said if the ledges are wet that does increase the potential for slipping for both human and dog. The granite is course which obvious can impact dogs with thin pads but my guess is less so than a stroll in the northern presidential summits. The only other caveat is on a day with a potential for showers or thunderstorms is that that steep section of trail has zero visibility to the west. The weather can move in quick and once someone tops out there is 1 mile stretch of zero cover to the summit.