Yes, for most invasive melanomas. For melanoma in situ, I often measure the distance between the tumor and the margin and add that information to the dermatopathology report. In certain anatomical locations (near eye, nose, ears, digits, genitals) or certain clinical situations, 2mm of clear margin...

My understanding has been that a re-excision of melanoma is based on initial Breslow depth. As long as the margins are clear on that re-excision, regardless of being 1-2 mm away from any one edge, there is no indication for additional surgery.