Hi Jordan
Give
http://obschevy.com/Pages/ShopOnline.html Obsolete Chevy Parts company a call. They don't have it listed online but they don't always list stuff that they have only a few of. They do have the little spring listed.
When I've talked to them on the phone they have always been helpful. If they do have some after you get yours let us know because I could use 2 to replace rust pitted ones.
This is the place that I found the NOS transmission last year.
Cheers Phil