Uh...no. Doan doesn't seem likely to have been responsible for either the Bangor or Proto Dome Gates because he apparently lived in Arris Dome his whole life, as had probably all of his ancestors after the Day of Lavos. (Sure, he apparently raced Johnny, but he probably never went into Proto Dome, as I would think if he had, Robo would have been discovered and possibly destroyed out of fear. )
Similarly, I don't think a Guardian Royal had anything to do with the Gate that appeared at the Lair Ruins in 65,000,000 B.C., though one might have been responsible for the Guardia Forest Gate(and thus subsequently the Bangor Dome Gate.)
I'm merely pointing out the possibility, not saying either way. I'll leave it to the more Chronoeducated peeps like Zeality to expand upon this possibility and whether it's likely or not.