Vaderisnothayden said:
I've wondered about that. In the end of ESB it clearly sounds like they don't know where Jabba is. The mention of Tatooine there confuses the matter slightly, but nobody asks why Lando is wearing Han's clothes, except in Family Guy.
Lando had just evacuated Cloud City. He left his wardrobe behind. That's obviously Han's spare clothes that were haning in the Falcon's closet.