Keycaps for Teletype Model 15

I spent a lot of time restoring my 60-year-old Teletype Model 15.
The first steps were devoted to cleaning, degumming and lubricating the mechanics for everything to work (https://www.youtube.com/watch?v=IluJW71h6ow).
To finish the restoration, I repainted the cover and I must also find or replace 2 missing keycaps.
As I could not find any spare parts, I made them using my 3D printer.