How to tell dates of Blue Note records?

I've recently begun collecting Blue Note records and love the sound of them. However, its difficult for me to tell the difference between the originals and the multiple re-issues. Is there a rule of thumb or guideline to telling which records are from which era?
a handy reference is the Record guide from goldmine which has a section in the front which lists most of the labels and explains which ones are from which dates such as capitol -rainbow green orange red etc. available at most book stores Barnes and Noble for ex.
where I have most difficulty is in determining the age of the re-issues, eg., are they from the 1980's, 1990's or 2000's as they all pretty much have the same label and look the same to me.
Tongue in cheek says any Blue Note that is not ratty looking is a re-issue!!
If the cover has strange stains, worn edges, greasy fingerprints.. the LP is covered with thousands of fine scratch marks that do not affect sound quality.. then you can be certain it is a 'real' original Blue Note.
I have never seen an original that did not look like H.
(All of the perfect originals are now in the hands of Asian collectors, or fanatics who will NEVER sell them.. they even take them with them when they die!)
I'm not selling mine!
Me either.
Yeah, I've heard the Japanese were paying huge bucks for them a few years ago.... now they're all out of circulation here in North America.
You could call Fred at JRC: