I'm not the Maven expert, especially for old Maven versions.
So I would recommend to upgrade Maven first.
You can run EJB2 applications with EAP6, but there are some necesarry changes for the jboss deployment descriptors (i.e. jboss.xml is ignored and you need to use jboss-ejb3.xml).
As you use EAP6.3 I assume you have a subscription and access to the Migration_Guide. Here you can find more details to migrate EJB2 applications to EAP6.
If you use the spec conform ejb-jar.xml this would work with EAP6, but the weblogic specific DD need to be migrated.
Also if you use CMP Entities it might be more difficult