Jay Leno, long without a manager, now at least has a high-powered lawyer in his corner, having retained Ken Ziffren, a partner in the entertainment law firm of Ziffren, Brittenham & Branca.Reached late yesterday, Ziffren confirmed that he’s been working for Leno but declined further comment. Ziffren was apparently retained near the end of NBC’s negotiations with David Letterman — which at one point raised questions about whether Leno would retain his chair hosting “Tonight”– in part to protect Leno’s interests. He’s been without a manager since Helen Kushnick stopped serving in that role for her ill-fated stint as exec producer of “The Tonight Show.” In another move signaling the severing of ties to Kushnick’s tenure running the show, sources say the late night talker will probably get a major facelift this spring, with such accoutrements as a new background set and curtain. NBC sources acknowledged that some cosmetic changes were under discussion but weren’t certain about when they would occur. Leno made a point of saying that he was flying alone, without an agent or manager, during a press conference following NBC’s decision to let Letterman–who was represented by Creative Artists Agency chief Michael Ovitz–go to CBS (Daily Variety, Jan. 15). Kushnick gave up managing Leno in order to exec produce “Tonight” but was ousted by NBC last September after a controversy erupted publicly over the show’s booking practices. Since that time, ratings for the late night series have stabilized and improved, with Leno running the show along with producer Debbie Vickers and co-producer Bill Royce.