Bone stock untouched is pretty damn rare, if it's running, more so and road worthy with current reg for $1000? I'd say next to impossible and you take your life in your hands driving it home if you can even find it.
Your truck, not running, with all the trim intact, minor rust and decent stock interior, worn but not beat to crap - $1500. Still has the gravel guard on the rear quarters!
Get it for less than that and you getting a great deal. '73-'75 are worst years for rust. GM used recycled sheet metal those years. They rust out even here in SoCal.
Make it run and stop, fresh tires, wash it off, gently buff out that original paint and drive the wheels off it.
I like lifted, big tire, off road trucks as much as the next guy but real value is in stock, virgin trucks.