I have not keyed a flat plate lock. I did several of the pin style locks in the late 70s. The door locks, if I recall correctly are the pin style. Those, I would just grab a few salvage yard locks and you should find a variety enough to make the doors fit your key. The ignition switch as Cletis mentioned is flat tumbler style. I assume you could take a similar strategy with it. I have an old ignition tumbler I was looking at and it appears to have a removable plate like the pin style for the flat plates. I am not sure how you would get it out of the switch without a key. I guess that is where the professionals come in.
