After a little more research it looks like the shock shares a lot of spare parts with the WP 4681 BAVP shock used on early LC4s and I think the early dukes. Turns out it's not a bladder design, but instead a floating piston keeping the nitrogen and oil separate.
Owners manual here:
http://www.fichier-pdf.fr/2011/02/04...ers-manual.pdf
...and a later version here:
http://ktm.kicks-ass.org/ktm/KTM_man...681%20BAVP.pdf
Rebuild thread here:
http://www.advrider.com/forums/showthread.php?t=653302
Kind of an obscenely huge shock:
As far as rebound damping is concerned, "mine goes up to 11."
