We don't know for sure. The lyrics are definitely new:
1) As you mentioned, according to Scott, the song was inspired by his new wife.
2) The song is going to appear on Dario Argento's movie "The Sandman" and you can hear a reference to Sandman in the lyrics, so it looks like he partially wrote the song FOR this upcoming film.
I believe Scott specifically said that it's not the same song once, but who knows, maybe it is partially based on that outtake and he just doesn't want any other people to take credit for it.
We'll never know, until we'll hear the track recorded by STP.
Also, can anyone post the music credits from the "Blaster" booklet? I wonder if Doug is credited for any song. If he's not, I think it is a total lie.