I had a Gibson IV for a while. Very nice bass. It was the standard long scale with a 1 5/8" nut.
I recall it being very comfortable to play, and very light weight.
I believe that Gibson used the same pickups in the IV as they did in the Thunderbird, so if you've got an idea of what a mid to late 1980's Gibson Thunderbird sounds like, you're pretty close to what the IV sounds like.
I only held on to mine for a few months. I ended up flipping it in a G.A.S. fueled frenzy, but I have positive memories of it.
Ohio bassist #25