I define fighting style as hand placement, aggression, head movement, defense, etc. Would Dempsey be able to do the things he did today considering glove size and techniques used today? If not why? Same with Greb. Not talking about Dempsey against the heavyweights of today or Greb against the middleweights/light heavies of today but stylistically every class from flyweight to heavyweight. Also any other old time fighters you guys can think of who's style would or wouldn't work today.
Great boxing is great boxing. The underlining skills of the sport have not changed however the ability of boxers to exhibit these skills certainly in the hwt division has. True ATG from any past era would shine in any era.