I've been told there's a tank from something like a Blazer, or maybe a Cherokee, that mounts in a similar location and has a similar filler that could be adapted .... I'd say if you've got an original tank, no matter how rough, it can be rebuilt, the shape and size is very specific to the location on these trucks, not much room to fiddle, the pickup tank wouldn't fit .... I happen to have a decent spare, but can't imagine what an expense and hassle it would be to ship it
Bill