You can usually tell by the shape and a few characteristics the covers have.
Here's a pic of some diffs. The d35 is there. The Chrysler 8.25" cover looks similar to the 9.25".
The D35 cover is oval, has 10 cover bolts, and usually has a rubber fill plug & hole on the passenger side. Some have a screw-in plug.
The 8.25" is more of an 8 sided cover & larger than a D35.
