I believe the 2 pin emblem has a plastic sleeve on the pins, that kinda presses into the steel sport hood. The 3 pin shaker emblem gets speed nuts on the inside preventing the emblem from shaking loose on the bubble from motor vibration.

I'm the CARETAKER of Weinstats '69 440 'cuda registry and have 104 of the 360 cars to date. 84 fastbacks/20 coupes. Always looking for new(REAL M-code) '69 440 'cudas to add to the registry so drop me a note if any are found or known. This isn't a publicly released registry. Thanks, Dave