$19800 for a retail customer on a 95 G320 4 door with everything working and a nicely "dialed in truck" is cheap. I buy and sell G wagons on a weekly basis. Please update urself on current markets. If you find one for a lot less please let me know as these days we need 4 door shells for build outs. What it sold for new is completely relevant considering the parts to rebuild the trucks are still quite expensive. Not sure if you have followed this post but we're currently finishing up a restoration on a g320 for a customer who purchased it new at the cost of around 38k. Most of that is replacing OEM parts. So again, totally relevant to the original cost. Expensive car expensive parts. I would imagine if you restored a 1995 Jeep Wrangler with all the same OEM parts it wouldn't cost you 38k in parts and labor to make it look and feel new again considering you can buy a new Jeep Wrangler for that. You can't buy a new Gwagon for that. So again, totally relevant.Correction - a '95 G320 with 200k+ miles is not "insanely cheap" at $19,800.
That's a very used G with not a lot of power, a 4-speed, and one that will need at least a good going-through at both axles and all driveshafts ($$$).
If it came with good service records detailing axle and driveshaft maintenance, as well as an updated engine harness, that could be a reasonable price provided the rest of the truck was decent.
Mid 90's G's have never needed "re-wiring". No one said they did. That's a misnomer. The M104's need new wiring harnesses, which basically unclip in a number of places, are removed, and then the new one is routed in and plugged into those places. No re-wiring.
What the truck sold for when it was new is also totally irrelevant. Lots of once-expensive cars are selling for peanuts now, especially with 200k miles on them. On the other hand, some cheaper cars are selling for more now than when they were new, or at least close to it.