saurabh_tulika,
1. RD - Receipt date - receieved by USCIS. ND - Notice date - date on which notice issued after assigning a case number. ND is the important date for all purposes. RD does not have any significance at all. some of us are posting only RD, because they may not have the ND as the employer may not give them a copy of the NOTICE.
2. As long as you send I140 and I485 before Jan 1,2005 you should be fine. Just incase, you cannot file your I140/I485 before 01/01/2005, you will not be able to file them for couple of years depends on your PD (Labor priority date. i.e., date on which you labor application is filed with SESA office).
Also, filing I140 and I485 before 01/01/05, does not mean that you will get your approval right away. USCIS looks like giving priority to earlier PD applications.