Can a receiver the same model as ones I have NOT rented from ATT work with my Uverse system?

Att if nothing else is very good at protecting its turf.  Settop boxes need to be authorized and provisioned in their backend systems.   I’m afraid you will be unsuccessful in your effort.  

any uverse boxes being sold online are stolen as at&t does not sell boxes they are leased.i see a lot of people buying these boxes or modems to avoid the equipment fee which cannot be avoided

To add to the above posts, while AT&T *may* provision your box to the backend system, you will then incur the $10 monthly charge.

What can you do? 

Call AT&T and have them add the box to your account, adding whatever fees they would have if you'd ordered it directly from them.  And when you disconnect service, they will expect you to return it as well... as it is still their property.

But if I were you, I'd return it for full credit and leave a bad review on the Amazon Marketplace for the seller of goods that don't belong to them.