.1860" on two TiMillie RIL
.1860" on G10 Walker LinerLock
.1865" on Fluted Millie (w/ early lockup)
My experience with Spyderco is much the same as referenced above. VERY GOOD about taking care of customers, but seems anything more than a pocket clip or screw means a trip to Golden (I have not even been able to get standoffs or back spacers for knives where friends have stripped).
A small piece of rubber (like from an inner tube, etc.) can be used to protect stop-pins & standoffs from pliers damage (I know, hindsight is 20/20 ... ;-) Possibly filing and/or sanding the high spots of damage might provide intern functionality while you source a replacement stop-pin.
Regards,