The Philco 18 came in a lot of different cabinet styles, I have the 18X Console with the slanted speaker board. I actually have 2 of these consoles, one of them I've had since 1960 when I was 10 years old. It was put in my Dad's old barn when I left for college and stayed there until 1993 when Dad passed away and we were settling his estate. It's in pretty sad shape but I couldn't bear to trash it. I found another 18X via ebay and as luck would have it it was only about 65 miles away, near enough to pick it up and not have to pay any shipping.
The model 18 is a real nice performing set, very sensitive and really great audio. The audio stages consist of a push pull pair of type 42 tubes in triode configuration that are driven by a single type 42 through a driver transformer. The set has a TRF stage ahead of the mixer that gives it extra gain and selectivity.
Philco's of this vintage can be a challenge to restore due to their use of bakelite block capacitors. If one is starting out to restore one of these sets it's absolutely necessary to have the service manual, you'll need to figure out what capacitors are contained in each of the bakelite blocks, some of them have one capacitor and others will have two and they are potted in tar.
Here's one of the best resource's I've found for Philco restoration.
http://www.philcorepairbench.com/index.htm
There's also pictures of several of the different model 18 cabinet styles
http://www.philcoradio.com/gallery/1933d.htm
I totally agree about leaving the original finish on the cabinet, your set is a nice original and IMHO should be preserved.