The idea must have been to start from the rear, bang the axle against the guide, and then pull backwards a little to get the wheel to move into the dropout. To run with the Osgear you'd put the wheel to the front (since there is a tension adjuster in that setup). To run fixed, you'd adjust the chain length by pulling the wheel back into the adjustable part of the dropout.

Looking at all of those proper vintage parts is torture. There isn't a wealth of that vintage any more.
I'm currently trying to rebuild some GB Coureur brakes because their center bolts are shot. Nothing much from that vintage is interchangeable...