Yeah that inside shaft cover being oily is what I noticed. Look at the cover on that side of the trans. I'll bet it is oily behind the output shaft.
Link to my thread and pic of the seal along with a Transmission Service manual in PDF.
http://986forum.com/forums/general-discussions/62312-help-identifying-transmission-axle-flange.html
PS Hadn't even considered that the clutch friction material sticking to the gear oil might be the reason the seal went out, but zooming in it does appear to have the black dust in the seal.....