I'm assuming your pic is of a 1200 ute taillight.

I had this problem awhile ago. Best to do what Datute1 suggests....cut the plugs off your old taillights and graft them onto your new lights. Or if your old light frames are in reasonable condition just swap the lenses over.

The repro lights I bought had small gaps around the lenses, but when I put those lenses in the original Datsun housings they sealed up fine ( indicating that the repro housings are badly
made).

It's a pain when you buy something that should be plug and play and you have to butcher it to fit