I have a similar one. It's a 2000 K3500 quad cab long bed single rear wheel "SRW". It is a 7.4 though. It's a "Camper Special" which all had gas engines. So that's different.
It's used as a farm truck, so the body is a little rough (that dent near the fuel cap is from before I bought it, 2012 I think). Here is a pic from 2016.