I have a door plate, vintage brass, with an edge detail on it.   I believe this is brass - a magnet does not stick to it .  It measures about 7" x 2 5/8" x 3/16" in depth.  It is a bit tarnished with  the tarnish showing uneven color on the plate.  The center hole where the knob goes is slightly bent.

Door Plate Brass Vintage Salvage Item