I have three Mk2 Curtas, One was the workhorse, one was the spare (very little usage) and one is still in it original packaging with the manual and warranty card…
They were my father’s, he used them when navigating in car rallies in the 60’s.
I think I was 12 when I took the bottom and shell off one. I just looked in awe at the guts and then very carefully put it back together.