I think you are right to pick Magneto as the base font. The differences you noted could have been simple modifications done at the same time the outlining was added. The basic shapes of the R and O are also like Magneto, and only the I looks like a completely new (and simple) letter.
I think those differences are relatively minor tweaks using a graphics program like Illustrator. You convert the lettering to outlines and then move some of the corner points around. I think these would be fairly simple modifications for anyone skilled in using Illustrator. Outlining can be done in such a way that it appears to reduce the letter weight, so I think this is still consistent with a modification of Magneto. The letterforms, slant, strokes and x-height all seem to me to be identical. Only relatively minor details have been altered. If I had this font I could try to demonstrate with a quick & dirty simulation, but my skill at this is mediocre, and an experienced artist would (I think) make these changes easily.
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