door hinges 55-59 truck

[noob]

I'm in the process of installing my door hinges and recently learned I put the upper on the lower part of the door and vice versa. My question is, does the rear of the hinge bolt to the cab? There are two bolts up front, but there is a single bolt hole to the rear of the hinge where it rests towards the firewall. Does anyone have pictures of the correct way to mount these hinges? My wife and I bought this shell of a truck with 5 plastic containers of parts that we are trying to make sense of. Any help is appreciated,