2 quetions 68 ChevyC20 build

[cjoenny89]

First of all this has been a long time coming and I am excited! We took this truck apart when I was 12 years old back in 1986 and now my son is 12 and we are getting back together!
1968 C20 bought new by my Grandfather.
1st question I was thinking about adding shoulder strap seat belts instead of just lap belts. Is there a good way to do this? Is that little cover up on the cab wall for a seat belt post mount? If I pop that tap off is there a threaded hole under it for a seat belt? If not what are those little removeable tabs for on each side of the truck cab about shoulder height?

Question #2 while I am putting the grill together on the 68 I am having trouble trying to figure out how to mount the blinker lights in the grill. I am wondering if I am missing a few brackets? Does anyone have any pictures of there 68 grills and the insides where the blinker light mounts?

The red truck just shows what grill I have the others is our project truck! with my son and my dad.
Thanks
Chad