If you are a Ludwig guy or girl you should check out Richard E.Gier's "Serial Number Based Dating Guides for Vintage Ludwig Drums".Not knocking Cook's book or any of the other lists but this is an eye opener,especially for 70's drums.Gier wrote the Gretsch dating guide that has pretty much been annointed as "THE Gresch guide".
What makes this one SO different is the MUCH larger sample of serial numbered dated drums.After reading this I believe two of my '76 sets are really '72 sets and one is a '73.Great to find out.