(Help!) Body bolts for a 74 Charger

Hello! Me again, lol.
Having issues with bad hex head bolts for my license plate and license plate light assembly. I went to three different hardware/parts stores to find these and none of them could help me out.

Does anyone here know what size or what type of bolts I need for the license plate and license plate light housing/assembly on my 74 Charger? The four that go into the bumper? And if anyone here could point me in the direction of where to go to order some, maybe with a link? Thanks a bunch!

https://www.amkproducts.com/about/#

Go to master kits, and select Chrysler, then chassis kits. If you don't find it, go to the bulk section. There is a ton of items that is not in a kit, but available separately.

license plate bolts are just like this:

1/4" ( 7/16" hex head ) captive washer

Light bracket is phillips screw with round head, but can't recall the size