The latest Warhammer ruling is that an ironfist can be used to parry plus it conveys a save throw.
If you're going to allow for the triple-whammy of additional hand weapon attack, parry and +1 armour save then at 15 gold crowns the item is still not unreasonably priced.
Further errata is not forthcoming, however, I would prefer to follow precedents being set for modern warfare on the field of battle.
Regards,
Werekin