3d printers offer a lot possibilities for manufacturing special parts. In particular one can use them to produce new or spare parts for old cameras. I collect my own models in a repository on Github and you can the STL files on Cults.
Some models are described more in detail on this site:
Rollei SL66 80mm f2.8 Planar lens cap
Lens cap for the Rollei SL66 80mm f2.8 Planar lens. It should also fit the 50mm f4 Distagon and 250mm f5.6 Sonnar lenses but I don't have them to verify the fit.
You can download the FreeCAD file by clicking here and the STL file here.