67-69 Cuda FB rear courtesy light
M&H, maybe:
Reproduction Wiring Harnesses for America's Muscle Cars
I recall my new harness only came with the left side wiring and socket for the interior lights.
I also recall the difficulty I had getting no answer on why, after spending $ for a 'complete' new harness.
I recall my new M&H harness had 1 small white socket, similar to the original black.
Their website is not the greatest, and they actually state they do not sell parts separately.
I did end up getting 2 larger white sockets, iirc. Since I went to led lights it's been a non issue, so I don't recall completely.
A quick search on fabo, and apparently the passenger side harness is available from M&H, part #41449, as well as the larger white sockets, however neither is listed.
Some state the led bulbs came with new sockets.
Can't hurt to call M&H.