If your GRS Viper needs a case, here's one for you.
The Viper is mounted using 2 - M3x5mm screws.
All of the buttons on the board (Firmware mode, Mask ROM, and Reset) are accessible through the top using a paper clip.

Print the bottom with support touching build plate and use Support for PLA for the support interface, if possible, for a nice clean finish.

This can be printed in multiple colors by assigning the color to the object. No need for cumbersome painting tools.