I misspoke... that is not a clevis pin, it is called a "hairpin". My local ACE had drawerfuls of various sizes. Too small and the pin can slip loose through the slot; too large and it's prong won't fit through the loop. A clevis is the cylindrical shaft that goes through something such as a hitch, and the hairpin goes through a hole in the shaft's end as a keeper to hold it in place, or it can screw through a shackle like holds our rock guards' hanger chains.
Though the hairpin doesn't seem to corrode, the slot area the strap loop feeds through and the old screw holes still do. I slopped POR-15 paint wherever bare metal was and in the holes, but even then corrosion is recurrent. Even spraying CorrosionX on the areas is unreliable. The acid corrosiveness is insipid.
I just have to keep watching for it, but when it's down alongside the batteries it's hard to get at without going through disconnecting and removing batteries. One of my old metal brackets is stuck in place down by a chassis battery causing "bloom", because it's little lag screws wouldn't come out. I need to cut it out one of these days, and POR-15 over it.
It's fortunate they put the slots where they did, whatever the reason, so the strap end loops can be tucked through.
Joel