1965 C10 - rear bumper license plate bracket bolts - info ?

[Woogeroo]

1965 C10 - rear bumper license plate bracket bolts - info ?

I have a '65 c10... and I bought a used rear bumper license plate bracket for it.

My bumper does not have the bolt holes in it, so I'm curious about what size bolts and things were used?

The ones I've seen in person look like the carriage bolts with the square part before the thread that it seats into.

Any information on the bolts or measurements on the hole placement is appreciated.

Thanks,

-W