Early Clash most assuredly is.
Yea, I never really got the idea that the Clash were really "Punk". I tend think of bands like The Exploited or The Sex Pistols. The Clash were always little more polished. That said, I would much rather listen to The Clash than the groups mentioned, and actually I think it's about time to throw a little London Calling on right now.
Bill
Have you ever heard the Clash's first, self-titled, album, or any of their first few singles? If that isn't punk, then neither are the Sex Pistols, Ramones, or Buzzcocks. Perhaps the trouble is people tending to think of the sound of London Calling as the sound of the Clash, period. That's like judging the Beatles entirely by the White Album.