1969 Fold down rear seat Bolt sizes

[BruceM-WA]

Hello Everyone, I had my seats Redone and the first guy that worked on them lost the bolts that connect the  fold down brackets to the actual seat frame.   Does anyone know the actual size before i need to take my whole seat frame to Lowes ? haha  I can't find any specifics online   

the image below is from a firebird, but just trying to show the 2 bolts (per side) that I am referring to

[camaronut]

These:  https://www.amkproducts.com/bulk-fasteners-products/?Product_ID=10081