It's not the same in that you can steelman a position and come up with brand new arguments that are better than what the other side is saying. "Reconstructing" doesn't necessitate the strongest form of the other argument.
I mean, that is what it's for. It's about making someone else's argument fit into your own system without misrepresenting it or making it unclear.
I suppose having "steelman" lets you relate it to "strawman" and "weakman" which can be an advantage, but knowing the existing term lets you read the existing literature.
> making someone else's argument fit into your own system without misrepresenting it or making it unclear
I think this is where steelman is a superset of this, in that it includes the reconstruction definition but also includes making a whole new set of arguments that are entirely unrelated to your own argument or the other person's argument. i.e. Steelmanning can involve coming up with novel arguments for the other side.
I suppose having "steelman" lets you relate it to "strawman" and "weakman" which can be an advantage, but knowing the existing term lets you read the existing literature.