Ah yes, that was clear, I just miss-read. (Metal frame of the focus screen... NOT the mirror!...I might have been unclear in my initial post, but just to be clear it was the metal frame of the mirror that was filed down, not the camera body....

Shame about the screen, but at least he got the film plane to register with it. Lets hope it stays that way.
PS: I've never shaved down a Hasselblad screen, but I have removed the frame so I could use it on a 500c...