Awesome survivor and cool story to boot.
I have one and don't remember if it was Johan or AMT but it has later model taillights (four round-ish ones). Mine, however, didn't fare so well over the years. I bought the correct taillights and bumper, like the ones you have, from Modelhaus before they went away so I can update it to match the actual. Also have the Rodders Journal (IIRC) that has the photo spread of the car and a good set of both original and Cady decals. Just needing to find a suitable chassis and then the fun begins.
Great stuff, these old OOP kits!