I wouldn't necessarily assume they are hardened. Their primary job is bending light gauge, aluminum and a non-hardened alloy steel would work well for that purpose without hardening. Pretty easy to confirm. Just run a file over the stem. If it skates, it's hardened. If it bites in, it is annealed. I damaged the point / end on one and was able to use a file to dress it up, if I recall correctly.
hardened tool steel is not required for bending light gauge aluminum. At least not in non-production situations.