After chopping her locks for her role as a pregnant homeless girl in the new flick “Gimme Shelter,” Vanessa Hudgens welcomed back long hair via clip-on extensions during Labor Day weekend. On Sunday night, Hudgens attended Gilt City’s final summer dinner in Bridgehampton, featuring Atlanta chef Linton Hopkins, at which she and a friend were overheard joking about heading to Montauk to meet “hot surfer boys.” On Monday, Hudgens watched the US Open match between Roger Federer and Juan Monaco in the Moet & Chandon suite with a close friend and her manager, both of whom are big tennis fans.