I don't know that I'd recommend thinking of body and mind as identical (as in identity theory in phil mind).

The proper relation is probably better thought of as instantiation of a mind by a brain, in a similar way to how transistors instantiate addition and subtraction.

It matters because if you think mind=brain then you may come to some silly philosophical conclusions, like that a mind that does exactly what yours does (in terms of inputs and outputs to the rest of the body) but, say, runs on silicon, is "not the same mind" or "not a real mind."

I don't have a pithy parallel quote from Korzybski to put alongside this (pithiness was not his style), but the ideas here are exactly in accordance with Korzybski on "elementalism" (treating as separate and distinct entities things that are not, including body vs. mind), over/under defined terms (verbal definitions lacking extensionality), reification of categories, and the rejection of the is of identity.