Most accurate serial number lookup?

[daOnlyBG]

I just realized Bob's Watches isn't necessarily the only serial number reference out there; that is to say, other websites (i.e., this one) yield different results.

I have an older Datejust listed for sale elsewhere, and after looking up its 5.8million serial number on Bob's Watches, someone asked if I was sure it's from 1979 and not 1980 (prob for birth year reasons). Naturally I searched for different sources and realized the discrepancies.

May I ask where the knowledgeable folk on this fine forum go to find reliable serial number years?

Thanks in advance!