The shape is fairly basic. I printed it front face down.
Because the OLED modules are made by various factories with slightly different dimensions I made the bezel to be fairly generous in dimensions. I didn't want to create something that fitted one module perfectly but be no use for others. As a result the module will need to be held in place with some sort of glue (epoxy resign or hot glue). The modules are cheap enough that I didn't worry about ever needing to remove it from the bezel. However if this is a concern then a few blobs of hot glue would be the best option as it would allow the module to be removed in future.