No, the raven lost his white feathers before Asclepius's birth. In fact, this loss resulted in the bizarre circumstances surrounding Asclepius's birth, since it was the raven's tattling nature (and, in the aetiological myth, punished by Apollo by charring the raven's snow-white feathers) that led to the death of Asclepius's mother. For details, review the selection that I assigned from Book 2 of Ovid's Metamorphoses or go to the raven option for the first question.
Apparently Apollo eventually forgave the raven. At least, they certainly look friendly in this painting from a fifth-century drinking cup, and since the raven's feathers have already been seared it has to be an after-the-event depiction. The cup is now in the archaeological museum at Delphi, where Apollo's sacred oracle was situated, although its style and clay composition indicate that it originated in the area around Athens.