I'm not sure any of the credit scenes should be considered canonical.
IIRC, while Fallout's history had states, they were conglomerated into Commonwealths a century before the war.
I'm not sure anyone would call Canada the 51st State, as opposed to the 14th Commonwealth.
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I will admit that while I was hoping for cameos this season, I expected them from the New Vegas cast, not from F1. Then again, if we are getting heavy Enclave action in S3, it does make sense that they would start peppering in characters now.