These were modeled after the original by hand. I have yet to test/print them - when I do, and find any issues, I will update the models as needed. Until then consider it a WIP!
I have been testing and printing this over the last few days, and found some minor issues. These have been corrected and updated, and should work properly now! However, I am not 100% satisfied yet, so I will continue to tweak things.
I have also now added the new back part with (almost all) text embedded from the original (I removed the non-text version, as that contains wrong dimensions now)
The author hasn't provided the model origin yet.