I just found the code in BlazeGraph that supports converting RDF reification into RDR. StatementBuffer.java:1425-1490. Its looking for this syntax:
_:sid rdf:type Statement .
_:sid rdf:subject <S> .
_:sid rdf:predicate <P> .
_:sid rdf:object <O> .
And it transforms it into the S P O triple, dropping the provided triples. This is consistent with the view that RDR is a storage level thing so long as the query parser does this backwards.
There is some commented out code (lines 440 to 705) that looks to try to handle the case for other non-/rdf:(subject|predicate|object)/ predicates but I'm reasonably sure it isn't complete and doesn't look like its compatible with the implementation in lines 1425-1490. And I'm pretty sure it won't work on full dumps without some more work around flush handling.