Yes.. If I remember correctly the breach was that a Fedora developer lost
control of his SSH key which lead to the compromise of a Fedora signing
server.
This _may_ have lead to the compromise of the signing keys and if you were
using some non-official repositories for your Redhat systems then there was
a slight possibility that the attacker could of wormed his way onto one of
those servers in the same way. It did not have anything to do with Redhat
'proper' other then that Fedora is ran buy a bunch of Redhat folks.