Dating an album

In my OCD, I've bought a lot of old records.As a newbie, I don't know much about them but when I looked, there was no date on them. Is there a way to tell the age by the stamp on it? Any other way?
Google is your friend.

Do you mean looking for the release year?

Try Discogs. Make sure you have the Matrix / Runout numbers (in the deadwax) for each LP in question as this will help in pinpointing which release it could be as there can be many.
Purchase Collectorz software to create a personalized library for stamps, coins, books, DVD, CD and LPs. Their website has a wealth of information to keep any OCD person very occupied
OK the label information is usually found at the record company site or there are internet resources that would supply the info about record label release years. Also can often have a release year information of a particular album if found and if there.
Most LPs from 1970 on will have the original year of release printed on either the Label or the Jacket.This of course does not indicate the copy you are looking at is from that year.It may be a re-issue.That determination is made by knowing the proper artwork that should appear on the label.
If any of them have bar codes, just do a search for the number. Be sure to include the first and last number. If not, try looking for fan sites of the actual bands. They usually have very detailed discographies.