old antique architectural restoration heating register vent

Old architectural heating or ventilation register vent. This vent has louvered front panel and two adjustable panels that open or close to control the amount of air movement. It is steel and not cast iron. The vent measures about 11 1/2" long and 5 1/2" wide. The mounting holes of the register flange are about 10" apart center-to-center. It has worn old paint and light rust.