You can get the lights from unity, but the correct brackets are a bear to find. The top of the bracket is curved to fit the lip of the area just so. I found this light on eBay WITH the brackets, that why I grabbed it for the $150.00. I still want to replace teh light switch but that's only 12.00, the wiring is a bit worn.
http://unityusa.com/default.aspxBUT If you pick a spot or do a roof mount or other spot where the metal is flat, you will have no problem getting a light.
I'm trying to do a 100% OEM period correct restration, so it was important to me (at least in my mind) to use the setup.