I have to say the size of the 1999 Cadillac Deville trunk seems to be on par with the size of my former Cadillac the Fleetwood Brougham De Elegance package. The trunk space is massive! I did a look over this afternoon and clean up. It has a nice spare tire and jack and the tire jack iron. If I ever get a flat I definitely would prefer a star lug nut tool.
You can tell by the side moldings the weather strip is doing the job. After all these years no rust or evidence of standing water. The trunk space is so deep it falls into a shade.