It is cast steel. Not stainless. Not a super-steel by any means.
Don't know where the "magnesium steel" came from, never heard that term applied to the 94.
It will not take bluing on the base surface & re-bluing attempts on the existing surface finish seldom go well. It will rust if you strip the bluing & underlying layer of iron off it and leave it like that.
It can be plated.
That steel was not a resounding success & was replaced by standard forged steel in the early 80s. Those who buy one like yours typically just live with it as is.