Everyone will have different opinions on this - i tend not to get too excited about keeping things 'original' - at the end of the day, the minute you put in LEDs, new decals or anything custom (even if it improves gameplay or protects things) it is no longer original.
My personal opinion is the neatest look is black (or colour on some machines) inside the cab sides, down to natural timber for the base. However sometimes i paint the base black - in my latest Monster Bash, it was because i had the thought of installing the cab decals on the inside (see restoration thread for pics) and thought it would contrast nicely. Other times i have simply been too lazy and not masked it up!
