My I-140's RD is 9/23/05. There is an LUD on 10/24/05, which is also my I-485's RD (my I-485 and I-140 didn't go in the same package). So this LUD probably means nothing.
I don't know if there was LUD between 9/23/05 and 10/24/05 because I didn't register until December.