While watching the trailer again I noticed the sensory dish on the Millennium Falcon was replaced, I wonder if there is an answer from the expanded universe (books and alike) when it was replaced. Even more important, did Lando pay for it :)
Unfortunately, the upcoming Episode VII - including its trailer - is completely un-related to any existing EU material. Therefore it's impossible to answer this question within the context of the film or any upcoming official canon.
Within the existing "Legends" canon, however, it's safe to assume that the Falcon's dish was replaced within days after The Battle of Endor. The novel "Truce at Bakura" begins the day after the battle, and mentions that the Alliance fleet is being restored to working order. Han, of course, wants to ensure that the Falcon has top priority. In fact, while leaving for Bakura a few days into the novel, we have this passage (emphasis mine):
Han Solo kept an eye on the Falcon's sensors as he swung the nimble freighter aside. Too experienced to get caught in the battle group's jump hyperwash, he couldn't resist watching until Luke's carrier - imagine the kid commanding a carrier group - winked out. Leia flinched.
Now he was back where he belonged, on board the Falcon. Alliance repair teams had wasted no time getting his beloved freighter back into service after Lando rattled her around inside the second Death Star (no hard feelings, Lando. It was for a good cause). He belonged in this cockpit, with good old Chewie in the copilot's seat.
Throughout the 30-year period covered in "Legends" canon, the Millenium Falcon was upgraded and refitted multiple times, including at least one refit which restored it to near-mint condition (a condition which Han met with mixed emotion). It was also painted a non-reflective black color throughout much of the Yuuzhan Vong war, an update which rendered it nearly invisible to the naked eye & other biological sensor methods used by the Vong.