If I recall correctly, there is an important difference to note:
The spark is caused by either the ferro rod chipping off and igniting, or from a part of the steel chipping off and igniting.
Flint itself is only special in that it is hard and sharp, and therefore able to chip off bits of steel. In that light, I would phrase my response as:
1) Unsure if any Stainless can spark easily
2) Anything hard/sharp can spark ferro
3) Flint can be used to spark high carbon steels (examples include 1095, W1, W2)