Hi Dan,
I found the file for your bass. It says I sent details on the build to you back in 2001! Amazing how long ago that is. Here's the list of specs:
top: Figured Walnut
accent: Maple laminate
body: Mahogany
neck: 5-piece Maple and Purpleheart
scale: 32 medium
fingerboard: Ebony
inlays: Pearloid (plastic) ovals
pickups: AXY
controls: Distillate
originally made for: Sam Ash Music
birthday: October 10, 1990
I have in the file that is was for sale at Bass Northwest at one point - maybe that's where you got it?
As for the Mahogany, it does indeed grow darker over time, and there is a wide gamut of colors it can express. Also, Walnut tends to get lighter over time, so the difference between the two may exaggerate the aging of the Mahogany.
Koa also gets lighter over time, and generally isn't red or ruddy colored to my eye. Post a picture (or email one to me) and I'll let you know what I think.