3-pins are generally shaker emblems, 2-pins are rally hood.I got "cuda 383" emblem, it has 2 pins. And I also got a "hemicuda" emblem, it has 3 pins. The spacing of the outer holes is the same. "Hemicuda" has an extra one in the middle.
Not sure. I have a challenger cuda resto book somewhere that gave measures for insignias and frame measures stuff like that i can look tommorrow and see if you got an answer yet