Before sunrise yesterday a gang of black-clad crooks smashed the glass of Emilio Pucci's midtown store on Fifth Avenue and stole heaps of expensive stuff. At 3:48 a.m. they grabbed brightly-colored dresses, T's, purses, belts, sunglasses, shoes and scarves, a spokesman for the designer told the Post, worth $100,00 retail of $34-$40,000 wholesale. Surveillance video captured the group breaking the shop's glass door, stuffing the pricey threads into big plastic bags, then fleeing before police could respond to an alarm, triggered by the break-in. According to cops, at least three thieves were involved.