Thats a good question. WebLogic 7.0 already supports
EJB 2.0. In fact most questions in the whizlabs simulator assume EJB 2.0 and specify EJB 1.1 wherever applicable.
To reduce confusion, I would now like to differentiate between the changes in the product (7.0 and 8.1) and changes in the WebLogic Developer exam (7.0 and 8.1)
Changes in product:
As far as the product 8.1 is concerned, there isn't a big difference between 7.0 and 8.1. If you have expertise on 7.0, that works for 8.1 as well. There are certain new features which 8.1 brings, but they are not as dramatic a change as they were from 6.1-> 7.0. I worked on both 7.0 and 8.1 on a project and migrating from 7.0 to 8.1 was easy.
Changes in Developer exam:
Now when it comes to the exam itself, BEA has changed the structure of the Developer exam to be more focussed on developing using WebLogic Workshop. It doesn't have the broad scope that 7.0 did. For example it does not cover basic administration, that 7.0 exam did. I also see the 7.0 exam being more J2EE oriented and 8.1 exam being more BEA oriented.
To answer your question about BEA endorsement, the only endorsement is that the author (in this case me) is BEA certified on 7.0. Having passed the exam and knowing the style and content of the exam, I was able to build the content to guide others.