I'm not at home to measure them and I could be wrong, but both guns will mount on my Navy cradle so I think the rear ears are the same distance apart on the M2 50 cal and the 1919. I think you can mount a 1919 on an M3 pod using the M3 T&E and you can mount an M2 50 cal on an M2 pod using the M2 T&E (although not recommended).
However, the two T&E's cannot be interchanged between pods due to the difference in diameter of the traverse bar.
Others can correct me.