Miserlou,
I flew the OY-BUM quite often, the registration fits the aircraft quite well.
Many moons ago, there was a C337 in Denmark with the unexciting registration OY-AGU. However tha danish CAA didn't like it when the owner added RK to the reg; in danish AGURK means cucumber. see
http://www.!!!!!!!!!!!!!!/open.file?i...tic=yes&size=L