M80-0110005 and M83-0110005 do use the same outer shell design, and in theory, can be used both in M80 and M83 female cable housings. The difference between the two contacts is the insertion force required to mate the male pin. The force is lower in the M83 than it is in the M80. This is done to assist with a lower total insertion force in a higher pin count, as the M83 can go up to 96 pins. Generally we would not recommend interchanging the crimps, as our testing has only been done with M80 contacts in M80 housings, and M83 contacts in M83 housings. However, you are free to do your own testing and confirm that the crimps work if you require.

We have a support article relating to this question, but essentially the hole you see is not designed to be an inspection hole. It is a plating hole, to allow the finish materials to reach the bottom of the crimp bore and help ensure performance. As such it is not relevant to IPC-A-620. Applying a crimp using the correct tools will indeed overlap the plating hole by 25 to 50%, but this is intended and expected. The design of the Datamate connector is so compact, there is no room to move the crimp area away from this hole without making the whole connector design larger.