Lufwaffe Nightfighter Airgunners claiming kills

[Jon]

Did any / many Luftwaffe Nightfighter airgunners claim any RAF heavies with their rear defensive machineguns. I would imagine on many occasions perhaps after overshooting a bomber the gunner would have had an oppertunity to engage his pilots target or perhaps even another bomber near by ?

Also if he did shoot a bomber down, was the kill marked down for him or his pilot?