Doom prototypes

I've been interested in these recently and I have some questions:

1. I saw on the wiki about the different prototypes of Doom for the 32X. How can you determine the date of it?

2. What does a prototype's chip board look like compared to the released copy?

1. The dates were probably marked on drx's prototype carts themselves (the guy who... made them available). But to be sure, you can ask him.

2. Not certain, but I'm guessing some protos' chip boards may be identical, while others have differences; definitely something to ask at the more specialized forums if nobody here knows.

EDIT: By the way, check your PM :)