Seat Belt Shoulder Bolts

I think I have the ones from my 74 swinger, do you know how to differentiate between the other seat belt bolts?
I think so, the lap belts were still installed and I kept those bolts together. They are shouldered and two different lengths.

I have some 7/16-20 1 /14 grade 8 long bolts that will fit but I’d rather have the original and shouldered to allow the top mount ( for shoulder belt) to swivel.