Whether you prefer the perfect antique lace veil to set off grandma's stylish wedding dress or simply seek a stylish hat, The Altered Bride may have your headdress. The Newbury Street salon, which also does fine alterations and restoration work on gowns, keeps more than 175 hats, veils, and headpieces in stock ($125 to $450).   With a selection that ranges from a lace top hat to conservative veils, it's a good bet that the staff can find one to fit, but if not, they will custom-make pieces to match a particular style or period gown.  And the shop's many shoes and extensive glove collection - more than 35 pairs, in all lengths and fabrics ($16-$130) - will finish off the look. - Clea Simon