There was a "Connoisseur Classics" version from MPC as well, and if I recall correctly, it was identical to the AMT version...same tooling.
I THINK the green-car box-art was street-roddded, and couldn't be built stock. Fenderwells for the spares filled in, no stock engine or rear end, etc. At least that's what it looks like from the partial kits and gluebombs I have. Art Anderson would know.
The fenders had scribed guide lines on the underside that you could open up to use fenderwell spares if you wished.