pashwin,
Our attorney filed both 140 & 485. When my wife received FP notice (in Mar 2004) she received only one. I talked to my attorney and he, too, was surprised to know that I received two notices. Both the notices have the same schedule date etc., but the letters were sent from USCIS with a week apart.
califdude,
The LUD did not change when I got the FP notices but it did change after USCIS received them from FBI