I thought he was playing his black Sadowsky with the altered pickup placement ala Warwick Thumb a few days back, but I really didn't get a great chance to check it out, so it might have been a Bongo. I just saw the black bass and assumed it was his other custom bass.
i remember reading on the ernie ball website that will lee had bought a bongo and was going to showcase it on the show.
I watch letterman regularly and while about 75% of the time he plays his tobacco sunburst sadowsky (without a pickguard and with a neck pickup cover) he also plays many other basses on the show too. the guy has many basses to choose from.
I went to see the show live right after Letterman moved to CBS and the Ed Sullivan Theater. Will played a Hofner that night, which I thought was really cool, considering this was the same stage on which the Beatles first appeared in the U.S.
Later in the show - they did a shot that showed his guitar rack - it had 3 basses in it and at the time he had switched back to the tobacco burst Sadowsky. I just had never seen him on that show play anything other than the Sadowsky. The black Bongo looked really cool.
I hear from people that would know that Will is playing that Bongo a lot (not just on Letterman). Makes sense - it's a good bass.
He had that bass 2 weeks ago for Les Paul's 90th b-day concert, might have had a white pickguard though... sounded great. I had the pleasure of working with him about 5 years ago, and he was playing his trusty Yamaha 5-string which he says is his favorite for recording
I would guess that the reason that one Sadowski is played so much on the show is that he probably keeps it there...That's one of those situations where since he plays that stage 4 days a week, he probably has a locker with a few basses that he uses exclusively for the show. I would also guess that it's in part due to the show's mixing and engineering. I can't imagine on a show like that you'd want to rock the boat for the production team in the booth. They know that bass and probably have a standard mix set up most of the time (then you could tweak away as needed per song or situation).
He also plays a white Ric sometimes in his Beatle tribute band. It's very frustrating trying to catch a glimpse of Will and his gear. I'm pretty sure he's playing through an Ampeg fliptop now too...anyone know if it's vintage or reissue? I say we do a write in campaign to Dave requesting that Will get all of Paul's camera time and while we're at it we should also write Conan to give Mike Merrit and his red Lull all of Max Weinberg's camera time. It's a tossup for me as to who's more creepy...Paul or Max. Does anyone even know who plays bass in Leno's band???
Mr Monkee is absolutely correct on the bassist and the reason EBMM is manufacturing lefty Bongos. Time to get onboard, Dude. The Bongo train is leaving the station.