Thanks for the additional detail. Aerial camera lenses were made with fixed apertures. I have a 3"/4.5 Biogon type that has a shutter but no diaphragm. And some were made with cast barrels.
Originally Posted by ausphoto
I'm not sure how to tell how many examples of a lens were made. The s/n smells like an Elcan one. These have the form tttt-nnnn, where tttt is the lens' type and nnnn is the individual lens' sequence number. There's no type 1095 in my Elcan C-series reconnaissance lenses catalog, but this proves nothing.
I'd been doubting that its an aerial camera lens because it seems to have come apart easily. The ones I've had (1 Ross, 1 S.F.O.M., 1 LOMO, 3 Elcan, 3 TTH, 20 Zeiss) were all made to be hard to disassemble. This to resist vibration. But again, if yours came apart easily that proves nothing.