If that was near me, it would be sold. You should be able to sell the fiberglass tub for $1k at least. The top is worth at least $1500 if it has a good and complete barn door. If the side doors have the glass, they are worth $500 each.
That is $3500, and we have not started going into the other unique postal items (shifter, interior lights, letter shelf, rear bumper, etc...)
Then you have the parts that are not unique to the postals; fenders, hood, grill, drivetrain, frame, etc...
If the top and doors are in good shape, it is easily worth $4k even with a rusted tub.