STLs can be split to parts in your slicer and changed color.
For the flush model part 7 and 32 were the ones I needed to make yellow, all the rest were black. Only needs to change filament twice so you can easily do it manually if you don't have an MMU/AMS.
For the recessed model part 12 and 13 were the ones I needed to make black, all the rest were yellow. There are 3 filament changes to get good coverage since the graphic is unsupported, still easy to do manually.
The author remixed this model.
Upscaled the model, thickened the hinge for strength, added tab for hinge tension, changed words and graphic on sign. Made models multi-part for easy multi-color printing. Made one version with flush face.