1930 CCPU Door Hinges How to Install

[C1Nelson]

Starting to put together a basket case 30 CCPU. As I look at the door edge I am trying to understand how to attach the hinges. I see three holes instead of something to thread the screws into. I was going to install lock washers and nuts inside the door but it looks that might interfere with the window channels? Possibly use a lock nut.

I have searched here and have not been able to find anything that explains how to deal with this.

Any help would be appreciated. Photos would be helpful also.

I did notice there are two holes at the top hinge and there appears to be a nut that has been welded into the skin of the door edge for one of the screws.