[Ed in Maine]

It is a few years since I took apart the body skin and door pillar and I can't remember how the top of the door pillar gets fastened to the top parts. There are two large countersunk screws, one smaller than the other. Can anyone tell me what kind of screws these where and their size. I assume they screw into the bracket associated with the top but why are the heads so large? The two holes in the top bracket that receive these screws are the same. Why are they heads so different? Also, my pillar has two very large bored and countersunk holes at the top of the pillar wood. Is this original and why is this necessary? Maybe a picture will answer these questions. Thank you for your help, Ed