Where to get part 87 for a KSC glock 17
 

http://tech.airsoftcanada.com/KSC/1-ksc-g17s.jpg

Repairing a gun for a friend.

Part 87 on that diagram. One of the little circle clips has broken off... I've searched redwolf, WGC, and pretty much everywhere. I'm wondering if anyone has an extra / knows where I can get an extra stock, or preferably upgraded one...

At this point he's willing to buy an entire lower.