awe man, you forced me to bring out the calipers...
The SgtFang and the MS1 I have sitting here are identical in every measurement I take -- even the crazy ones. The aspects of asymmetric warp-age are also identical. I have always assumed this to be the case, but the numbers just don't lie.
...still, once you shave the RF ear cap off, the upper RF ear base on the helmet is too narrow, so that will take a bit of bondo/build-up to make it wider for the inner ear cap.
I had never heard the MS was a build on a DP95. It looks every bit of the same lineage.