67 Stepside Tail Light Bracket Bolt Size

[josuito]

Hello guys, maybe this will be a stupid question but I'm done with this.
I need to know what size bolt goes in the tail light bracket to hold it down to the truck, is a 67 c10 stepside, I'm not a Pro so I was taking and buying bolts from here and there with no luck. I even got the ones from LMC and they sent them wrong too. The closest one was a 5/16" but the pitch is the wrong one it seems.

Any help will be appreciated.

Thanks in advance.