To reconstruct the door hardware, the first step was to investigate the surviving doors to determine if any physical evidence of the locks survived.  To find the evidence a light was raked across the surface of the door where the lock or bolts may have been installed.  Under raking light it was often possible to see where Madison-era screw holes were located, the outlines of lock hardware like escutcheon plates, and even where the locks themselves had been mounted to the doors.