I had a couple missing. Got a few long whatever mm those are bolts, cut the heads off, and roughed up that end. Epoxied the hole, and half screwed the bolt in. Then sat an appropriately sized washer down, to fill in the gap, and mimic the flange on that bolt.
They seem to be holding very well so far, but I'm sure you could have figured out that much yourself, and looking for a more factory option. I couldn't find any either. Though the holes in the SMC get tore up also, I epoxied in some loose ones too.
If you had them made, you could offer any any packaging really, but man I dunno if you would be able to turn enough of them to deal with it all. You're going to have more people that probably don't want to buy a set, but that also leaves you spending years or whatever nickel and diming single or double bolt sales, with shipping that's probably going to cost as much.
If you had them made out of 304 stainless, I could see more people looking to buy a set for both fenders. Though in general I'd rather have nylocks, than the nuts that GM used. Perhaps only have the studs made, but then you run into purists that want an exact styled nut, lol. I'm a bolt nerd though, and generally replace everything with stainless or titanium. I dont care about factory, I want better.
I think if I were you, I would just ask myself if the cost, and storage is worth getting yourself some factory bolts, and anything you make back to be a bonus. Not trying to do it as if you need to then unload a lot of bolts to help cover it all.
