I am not sure if I understand your question.
What are you using to package your project? Are you running through a tutorial? or are you using JBoss IDE?
You might be packaging the classes twice so that you have one archive that can be deployed on the server, the -client.jar can then be given to remote clients that will be accessing your beans.
The client jar would be restricted to just the interfaces that the client need to see i.e. the client does not need to see the bean implementation.
I was running through the tutorial and asked myself, why /bin folder was packed two times. But if I understand you correctly, the client-jar does only contain the accessible Methods without the implementation?
Thx for the help