What parts does that "rolling body" come with?
It makes a huge difference....especially when you start pricing the replacement parts.
Some "SWAGs" at pricing for items you need:
Hood: $300
Front Fenders: $150 ea
Repro Doors: $250 ea
OEM Tailgate: $300
Singlewall Top: : $1000
(or) Doublewall Top: $50
Original Seats: $200/set
Rear Seat holdowns: $100
Rear Seat: $100
Carpet Trim Strips: $LOTS
Repro Interior Bedside Panels: $500/set
...
...
and on, and on...
The more of these parts that are included in the sale, the higher the selling price will be. Even a "cheap" rolling chassis will cost a few thousand more if it's missing a lot of the critical parts you need. So don't be seduced by a low initial acquisition cost.
IMHO, a '69K5 specifically will command a higher price because of the significant rarity compared to the '70, '71 and '72 production numbers. There is also an implied responsibility to maintain it's authenticity as much as possible to preserve it's value.... if you want a truck to hack up, do it to a '70-'72K5.....or better yet, to a later model "dime-a-dozen" K5!
From your .sig it looks like you already have 3 project trucks AND a daily driver....do you really have the time and financial resources to take on another project?