Jozef says in [WFLY-476](https://issues.jboss.org/browse/WFLY-476)

> Basically any archive that has a session bean or a class annotated with CDI scope definition is an implicit bean archive. Any existing ejb-jar is therefore CDI-enabled in EE7 (assuming it contains a session bean)

So my understanding is that it would return false if you neither have a beans.xml nor any CDI-scoped bean nor a session bean.