Here is a hint for you. If you are buying cB0, they should be SL45Y, if boxed.
The batch number is on the box. So is week, usually something like Q032 That 32 would be the week. Q is the plant, I believe malay. The zero is the year, ie.2000.
The main thing is, ask the vendor and specify if you can. If they will not tell you or refuse to cooperate, then find someone who will. SL3XX is OEM bare cpu, but your chances of getting good chips are lessened there, as many pretest them and put the failures back for resale to the unsuspecting.