I'll make this even easier: Dabura=Perfect Cell>SSJ1 Gohan(Cell-era)>>SSJ1 Gohan(Buu-era.)
Even during the Cell Games, when Gohan was FAR more powerful, he still HAD TO become a SSJ2 to become more powerful than Cell... When he was merely a SSJ1, Cell stomped him rather easily. That said, Gohan couldn't have possibly stalemated a Cell-level opponent(ie. Dabura) as a SSJ1 during the Buu-era, given his VAST reduction in power at the time.
In short: Gohan literally MUST HAVE been a SSJ2 against Dabura. Anything less would have been stomped... And effortlessly so.