Gap above fireplace surround

[Jon mackay]

Is it acceptable to have a gap above a fireplace surround?

[wayne soper]

Yes, and NO, My comment would be that burning embers may enter the room and I would not trust that unit .
Aside from that it's a square peg in a round hole and looks like Sheeeeeeeeet
Of course the use of that fireplace with no cover or screen at all is completely up to the owner and if they choose to live with it like that, good luck to them!