I'll start off by saying this is my opinion and there are lots of opinions out there.
Our trucks are worth what prople are willing to pay for them. If you love 'em and gotta have one, you'll be willing to pay more. If you are indifferent and it is just another old truck, obviously the buyer is not willing to pay more. Be careful with using the terms true survivor, matching numbers , COPO, all these can be overused by folks just trying to raise value. Calling a small dining area a breakfast nook for charm doesn't add $$value.... I was really interested in a car that was described as original, matched numbers, yada, yada... no pictures. Got the pictures, it may have been original and it's numbers may have matched but it was a POS not worth investing time and money.
Sounds like your description is of a nice truck, expect a little more money. Obviously short beds are worth more than long beds... if I were looking for another truck to rebuild, I wouldn't pay that for a long bed. If I was looking for a daily driver or work truck, I wouldn't pay that for a truck. I might if I wanted to preserve another 46 y/o truck that I love and want to keep it on the road and turn heads!!
It's your opinion that matters when you decide what you want for it if you sell. If someone doesn't want to pay, don't sell.
Good luck