This old thread may be helpful for pin information. Do a search, there may be more. I wouldn't get your hopes up, I never found any. It's an odd size. Also all the seal kits and pistons for the MK1 P432A's are gonzo. The kits for the P432D "black" calipers might be useful, but be advised the pistons need to be shortened because the MK1's don't use the outer dirt seal. Also, for what it's worth, you can "rebuild" calipers w/o unbolting the bodies by popping out the pistons from one side only, and then replacing the old piston rings.
http://www.ducatittandf1.com/viewtopic.php?f=22&t=10079&hilit=quick+release+pinshttps://www.oppracing.com/product_display/361452-brembo-oe-seals-replacement-kit/