5 POSITIONS AND 5 CUT DEPTHSThese cars and locks are 50+ years old. Try using any other Ford trunk key you have laying around, wiggling it and moving it in and out a bit while you try to turn it.
There aren't that many different trunk key combos (what are there, 4 or 5 positions on the key X 3 different heights? I'm not doing math at 8am). Combine the age and wear on the lock with the relatively low number of combos and it shouldn't be too hard to get another key that's close to get it to open.
Assuming you've got some extra Ford trunk keys laying around and haven't drilled out that separator plate yet.