WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
Building, troubleshooting and testing of these amplifiers should only be
performed by someone who is thoroughly familiar with
the safety precautions around high voltages.
Heh, I think when they invented the tube numbering systems, they expected that a show called Starwars would use those numbers and thus omitted them from use for tubes...
Also, tubes starting in R or C would probably be rare european speciality tubes and almost impossible to find too.
I have a program database of almost every tube ever put into production. You can search for a number and get pinouts, specs, uses, and some other numbers and names, also, substitutes.
I searched for R2D2 and C3PO in there and found nothing.