At the time of ROTJ, it had probably been a few years since Boba Fett even heard Lando's name, much less seen him. I doubt Fett had any reason to expect to ever see Calrissian again... And what reason would Fett have to keep Lando's "profile" on hand, anyway, assuming he ever had it to begin with, when there are undoubtedly hundreds of thousands of outstanding bounties that he could capitalize off of.