“ If A. O. Zischang could build himself a gun while working for Lefever and then go on to bigger and (presumably) better things in the gunmaking biz, then why not J.A. Prechtel?”
Please keep in mind that I have only see pictures of the Zischang marked shotgun and have not handled it. I would be very surprised to learn that Zischang built this shotgun. I would (no disrespect to LeFever owners) expect something from his hands to, well, shine.
If the present owner of the Zischang-Lefever would post some pictures of the gun I think it would be interesting to all.