I would give it a shot, myself. If nothing else, have the hardness tested by a machine shop, see how soft it got. It could conceivably be close to proper hardness, and would be fine. If it hasn't slumped or warped due to heat, it seems fairly salvageable. Biggest concern would be that it may warp in the heat treat, which would waste the effort. Maybe find a knifemaker locally with a salt pot heat treat set-up, they may find it an interesting project.