Here's a procedure including drawings and photos on how to clean and rebuild Ball Lock Kegs.
In particular there's a photo of the four different kinds of poppets and the keg types they are associated with.
This is a nice procedure to keep handy. Actually this was drawn up by our very own Mike Dixon.
http://hbd.org/carboy/ballkegclean.htm
Type A is for Spartanburg or Firestone Challenger V, VI, and Super Challenger.
Type B is for Cornelius.
Type C is for older Firestone Challenger (no V or VI) and John Wood 85.
Type D is for older Firestone models A, R, RA, and RC, Alloy Products and John Wood (pin lock).
Cheers,
Ron