This Raspberry Pi 4 case is based on the TRS-80 Color Computer, Model 1.
The top and bottom files should be printed using silver filament. I used Tianse Silver PLA because it's so close to the original color. The keyboard back should be printed in black. The keys themselves should be printed in white.
Since the keys are designed to be inserted into the back of the keyboard back, they can be painted the correct colors before being inserted, without causing a mess on the finished keyboard.