If you actually mean the sole edge dressing, then yes, anyone can do that. If you really do mean the welt, then he probably won't replace it for the first resole so you will still have the original welt. If he does replace it, he can do so with the color of your choice. Any of the above is pretty routine work for any competent cobbler. At least with my Carminas, the sole is trimmed so close to the upper that the welt isn't that visible/noticeable.