NavList:

Instructions or identifying which knobs moved which counters would be useful, also an indication whether the outputs were on the front or fed out elsewhere like the ’Astrograph’.  At first, I thought the two circular dials on the front might be intercept and azimuth, but ‘Solar Declination’ hardly means azimuth.

AC41 – 12 on the information panel might mean the 12th of a batch produced for the Air Corps in 1941 like a U.S. aircraft tail number, or it might just be Stores Ref & Section Number e.g., 6B/47 for the 47^th type of air navigation device in section 6B of the RAF’s list of equipment, i.e., the Douglas Protractor.  

By 1943 Mr Fairchild wrote AF43 5555 in the same position on my A10A sextant, and Mr Link wrote something very similar on my A12 sextant.  My A10 is too corroded to read its name plate.  Mr Wikipedia says the USAAC was superseded by the USAAF on 20^th June 1941, was abolished as an administrative organisation on 9^th March 1942, and was finally abolished completely on 26^th July 1947 when USAF was formed, so my first suggestion as to date and the number produced sounds correct.  DaveP