The inner panel has one large hole that the light housing sticks through, plus two small holes for the mounting studs. The large hole is 1-7/8” in diameter, and I didn’t have that size, so I had to wait for that to arrive in the mail.
I made a wooden template from a 2×4 to locate pilot holes for the three. I goofed on the orientation of the holes on the RH side and didn’t realize it until the first test fit with the lamp. Oh well…two extra holes.
I had to grind the big hole and enlarge the stud holes a bit to get the lamps to fit properly,
a quick spray to seal up the bare metal, and on to final assembly.
A little touch up and… just need to hook up the wiring.