MATT - Spirol roll pins.... SPIROL IS the manufacturer....and there's ONLY one of them. My Hardware Buyer here at work is gone right now but I suspect they only have a single plant and EVERYONE Buys US made spirol pins from them. Of course there are imported parts, China, India, Turkey, Korea, etc. etc. etc. When You get into other types of pins like the solid hydro drive pin on the engine coupler there's a company called DRIV-LOC that makes a pin with a groove scratched down the side that could be used in a worn coupler/driveshaft to retain the pin.
I have a three-ring binder four inches thick here at work with NOTHING but specialty fasteners, pins, clips, snaprings, You name it.
It's true IHC used to make lots of threaded fasteners at their West Pullman, IL plant along with distributors, magnetos, small pump gears like for engine oil pumps & hydraulic pumps....but they also BOUGHT WAY more standard bolts, nuts, & washers than they had capacity to make.