They are only available used. I have one that needs a patch panel welded to it. I have the patch panel as well. I would part with it for $30 plus shipping of $60 by greyhound. The right wheelhouse is the hardest one to find. They are usually rotted from battery acid outgassing. Whenever I find a good one I pick it. I have a set of 91-93 wheelhouses. The 91-93s will bolt up to the car, but the holes for the accessories are different. I do not want to split the set of 91-93s. I am asking 120 plus $70 Greyhound shipping for them.
The Caprice sedan, and all wagon wheelhouses are the same for 91-93, and 94-96 cars. The Roadmaster sedan wheelhouse may also be usable with a little reshaping for the different wheel openings. I have not tried it, but they look basically the same. If the running length of the opening is the same, you could just reshape the curve a little. There aren't any 94-96s with good wheelhouses in the yards here right now.