Thumb rest for Rickenbacker 4003 (Recent models 2014-2017) that fits without the need for any modification to the bass. There is a standard version or a bevelled version. You can choose which ever you prefer. The bevelled version does give more room if you still want to rest you thumb on the neck pickup.
My Rickenbacker is a 2017 model and I believe that any model prior to 2014 may have a slightly different spacing between the mounting holes, so this will only fit newer models. If you send me the exact measurement between the two mounting screws on the scratch plate. I could modify the design slightly to see if it fits.
You don't have to print at a high .50 or .100 resolution but as it is a small and quick print, you might as well go as smooth as possible especially as a Rickenbacker deserves the best :-)