Yes, that was part of Archer's bio in that episode, although that particular part was not on screen. It would be nice to canonize it in Star Trek XI...even if all we see is an old man sitting in a seat clearly reserved for Jonathan Archer. the character doesn't even have to be Bakula or have a speaking part. Abrams is known to throw out curve balls like that, so I wouldn't be surprised if we see Easter eggs like that connected to all the series.
The Borg King being an assimilated Matt Decker? Interesting idea. Perhaps the planet killers were Borg toys? Or...a type of Borg wormhole that sucked Decker in?
OR...OR...perhaps it's Will Decker, after he joined with V'Ger. I know they were different actresses, but maybe the Borg Queen is really Ilia?