A very nice local couple dropped by the hangar today and donated a brand new, unused Type K-3 gunsight assembly, still in its original shipping crate with original wrapping plastic and dessicant packs! This unit was made by N.C.R. (I assume that to be National Cash Register). My research shows this sight was used on the Sperry Type A-1 mid-upper turret, which was used on the B-17E/F/G models. If anyone knows this to be false, please let me know and I'll edit this post with the corrected information.
Here's the data plate:
Here's Sammy giving the new arrival a "cat scan":
A view of the opposite side, after Sammy had finished her scan and was satisfied that the unit posed no threat to the Museum staff:
These nice folks made the donation (names withheld):