Just did a quick internet search for "GM screw 9419380." Heartbeat City (HBC) Camaro among a few other restoration suppliers who also list the same screw. HBC's is the 1st pic below and list their screw as an original NOS screw, but it appears identical to AMKs screw. AMK's current listing is item #B-12175.
HBC may have purchased the screw from AMK Products. Years ago AMK began buying up unused bulk hardware items from Ford, GM, and Chrysler assembly plants as the plants closed. Most of AMK's hardware may be NOS stock.
All told, ideally it would be best to compare side-by-side AMK's 9419380 screw with a known GM original from a survivor Camaro.
I thought I solved my 9419380 screw mystery...but here I go again...lol!
