The finished installation in the daytime.
The reproduction dome light assembly and the clear lens are both from LMC truck. I was very happy with the parts, which is not something I can always write about with LMC parts.
The reproduction dome light assembly has plastic snaps on the back that line up with the screw holes in the cab. You could drill a hole in it, if you wanted to I suppose, but I just snapped mine in.
I also bought the clear lens at the same time. It really puts out a lot more light, even with the standard bulb.
Oh yes... the dome light assembly came with the opaque cover and a bulb already in it. Just in case anyone wonders.
I never could get the plug to fish through the cab... I was cold, wet and rather mad, so I just cut the wire, fished it through, spliced it and went on with my day.
Thanks to everyone for their suggestions.
-W