lilpup
i gathered all the information off of xbox 360 drives database (mines listed too under lilpup), and tried to see if there was a pattern on manufacturing dates, the first list below is the manufacturing dates for each drive and the lot numbers. the second list is manufacturing dates, and the drive that should be in that 360. this is not 110% accurate though.
manufacturing dates: fw: lot #:
4-29-2010 to 12-30-2010 9504 1019x-1133x
11-10-2010 to 11-11-2011 0225 1046x-1132x
4-9-2011 to 9-5-2011 1071 1116x-1142x
3-11-2011 to 8-19-2011 0401 111x-1134x
5-26-2010 to 10-17-2011 0500 1045x-1143x
8-4-2011 to 9-22-2011 0502 1132x-1142x
8-1-2010 to 11-3-2011 1175 1133x-1145x
manufacturing dates: drive that should be in it:
Apr 2010 - May 2010 9504
May 2010 - Dec 2010 9504/0225/0500/1175
Jan 2011 - Nov 2011 0401/1071/0225/0500/0502/1175
so lets say you wanna find a slim with a lite-on with 9504 firmware. the manufacturing date is april 2010 to december 2010. but the hitachi 0500 And lite-on 0225 was also. so if you find a 360 slim with a manufacturing date of Apr-May 2010 its a 90% chance its 9504!
my manufacturing date is Feb 2011, and its lite-on 0225. which according to the 1st list is correct.