[Jeph]

I don't know if there are differences other than what you've listed ("ears"). There's a chance that if the top is relatively older than your car, the paint could be faded differently. It just depends on how the previous owner took care of it (and how you've taken care of your paint).

And they all rattle, regardless of the year.

Lastly, I don't know if there's really a way to tell the difference in the year of the top (except with those old ear-y ones). I don't think they have a year, just a manfactured date. But the closer you are to your year, the better off (my opinion).