Save the gas. Ferrous metals can easily be manipulated(for hardness etc) in good old fashioned fire.
For some steels, yes.
When you want to make tools and heat treat tool steel, it is best to not add anything to the metal by way of impurities in the fire. That’s why I like propane or other forges where I get a nice, clean flame. If people really want to be prepped for making their own tools, they should lay away from O-1 and A2 tool steels. Very useful stuff.