Kal,
I'll ask for a more specific answer next time I speak to him, but the tech who advised me hinted at "substantially identical" as I recall. He never flat out said it, though.
I do remember that he mentioned a few small differences, and he kind of chucked at the notion that they would make a difference in performance. I'll follow up here after my next conversation with him (if I get anything worth posting.)
However, it is possible that Onkyo discourages specific disclosure from the dual authorized service shops - for obvious reasons. I'm not sure where you're located, but my guess is that there is such a repair company local to you. Since you are such a charming fellow, you might be able to get the answer for yourself with a carefully worded inquiry.
Marty