A member here found an old Spiegel catalog advertising these for sale, not sure if similar rifles were sold through other distributors or not. We call these salesman samples sometimes, but that's tradition more than accuracy.
Seen from the late 30's into the early 40's, early ones with checkered buttstocks but not forearms, later ones with both checkered. Sling studs and also d&t for some kind of scope bases, though we've never seen one with a scope mounted to it.
Here's the original link where Hemlock_Ranger found the catalog.
http://www.24hourcampfire.com/ubbthreads/ubbthreads.php/ubb/showflat/Number/2243582/page/1/fpart/1Here's the ad: