Well, I just got my rear rotors, and

they are even deeper than the 951 rotors I have.
Gonna send 'em back and see if '86 944S rotors are what I need...
EDIT>>> I fingered it out! I have EARLY ARMS! Mine have bumpstops and the later ones don't, apparently. I remembered the post from superman a couple of years ago about their differences, so I dug it up and sure enough that's where my goof came from.
Soooo...