Here is the other variation with a white plastic cap.
I have a couple of cases that have a notch cut in the rim but without a sidehole for crusher tests. I don’t know if these are legitimate (yours appears to have a proper neck crimp) or assembled by someone who had access to components.
This is an interesting case type with a number of distinctive characteristics that speak to the evolution of the design. The first loadings have headstamps and an angular extractor groove.
The next step with modified h/s bunter and extractor groove which now has a radius.
The final version has the rounded extractor groove and no h/s.
The program was cancelled in the the early 1990’s.