aterry33,
Your confusion comes from trying to associate engineering revisions (the number after the dash) with features. Engineering revisions are not meant to indicate features or configurations. Engineering revisions are there so that the correct part for a repair can be ordered.

A engineering revision is only incremented when the change to the firearm would require a different part than the preceding revision.

For example, the -1 engineering revision of the model 442 was a change to the J-magnum frame. Because of the stronger frame the firearm was now rated for +P. However if you had to replace a cylinder you would need to know it was a -1 as opposed to a no dash because the cylinders are different lengths. There are other parts differences as well.

Your revolver is marked as a -2 because the correct internal parts are -2.