These white phenolic "spacers" are meant to keep the bump stop from hitting the top of the damper and possibly damaging the seal on your front Koni struts (on your 86 and/or 87 Shelby GLHS). 
 
Pick up a set now while you still can in case yours are missing or damaged, or if you'd like to keep a spare set on hand for future rebuilding of your Konis.  Next time you have your GLHS up on a lift, peek into your front struts (around the springs) and see if yours are there, or missing.  Price is for 1 spacer.  Each GLHS requires 2.