Different Diffs ID?

Larry and List,

I may have what Larry needs, but;

I have a couple of diffs from several different years.  I'll need to
identify which is which.

Can someone lead me to the proper info for identifing these, (what numbers
or markings should I be looking for).  What would the tooth count be for the
different ratios?

Thanks!

Kevin V.
(Not knowing the different diffs differences........)