In the Silent Spot, Red mimes a fisherman being bothered by a game warden (Jackie Coogan). The Snobs, a British musical quartet that dresses in 17th-century attire complete with powdered wigs, makes its American television debut tonight. The four-man combo consists of John Boulden (rhythm guitar), Colin Sandlander (lead guitar), Peter Yerrall (bass guitar), and Eddie Gilbert (drummer). They are 17 years old. Their first record released this spring in England, is titled, appropriately, "Buckle Shoe Stomp," and was recorded at a Buckinghamshire mansion called Medmenham Abbey, built on the site of a 12th century monastery. Costumes for The Snobs when they perform include silk shirts and cravats, blue velvet jackets, buckle shoes and lace handkerchiefs. Their clothes may be 17th-century but their music is 20th-century rock and roll.