I'm pretty sure 665/7 is the part number for Zeiss 9x12 plate holders of the "Normalfalz" type. The Voigtlaender film-pack holder would be consistent with this (Voigtlaender used the same standard for holders).
You'll find plenty of people over in the plate-camera forum who will have a use for these. (Not me; I'm pretty well set for 9x12, though I still need some holders and a ground-glass back for 6.5x9.) Or you could develop a plate-camera addiction of your Very Own. :-)
-NT

