Rules Questions thread

Continuing the discussion from Necro Tech II: How good is it? What's the game plan?:

Can a Blackhand Resurrector summon a hero if you couldn’t normally have that many heroes in play? For example, if you have 2 heroes in play and a Tech II built, could Blackhand Resurrector summon the 3rd one even without having Tech III or a Heroes’ Hall? I ask because nothing on the card or in the rulings for the card gives any indication either way.