'79 ex-diesel C10 LWB-need some tips
 

I have a 79 C10 LWB that started life as a 5.7 "Olds" Diesel. My uncle bought it new. The diesel broke a rod one night coming up Monteage mountain in about 1988, so he pulled it out and replaced it with a gas engine. It now has a '70 "Rocket" 350 from a Cutlass. All the diesel wiring and relays are still in place and un-cut. I am adding a gauge dash. Here are a few questions:
1-is there any demand for these trucks because they were originally diesel and don't have to pass emissions?
2-does having the original diesel wiring help any? (original diesel engine long gone). Does anyone actually put the diesels back?
3-It originally had no dome light. does adding a factory dome light help or hurt the value? I don't want to cut that big hole if it hurts the value.

I don't want to spend a bunch on it that I won't ever get back or do things that hurt value. I'm just curious what upgrades would help and not hurt in case I decide to sell it sometime.