Since then I've cleaned all the interior, moved the rear and front bumper inwards since the plastic bumper fillers was totally crumbled, renovated the Olds 307 engine, installed right hand electric mirror, fixed the power window switches, exhanged the power door lock switches, rust protected the frame and undercarriage and other tlc as well as full service. This car is my daily driver, so it doesn't need to be perfect, just in good operational, clean status. I have also renovated a second spare Olds' 307 engine, just because I had one.
Those fillers were a big problem. My FRONT fillers were in good shape. Didn't have to mess with them, but the rear fillers were already cracking when I got the wagon in December, 2012. Little by little they completely disintegrated. Bought a replacement set, made out of Fiberglas, which weren't an exact match, particularly the big center piece. I was not going to use it. I came up with a plan to replace the center piece with some parts bought at my local hardware store, but sold the wagon as-is before I tried it out.
Yes, I have friends with Cadillacs who bought repopped fillers with really bad fit. Perhaps the fillers were never had a snug fit even when new.
The end cap Fiberglas replacements would have to be reworked, sanded and shaped - quite a job, and something I've never done. The original factory material is a urethane plastic, better for complex 'soft' shapes, but hard to make molds for....... The factory probably did injection molding.