I have a 12ga hammer double marked W Richards which has a left hand side lever. Whether they are real or faked I really don't know but this gun has Birmingham proofs. It is definitely "Not" either a Westley or William Richards made gun. Although in rather poor condition it appears it was likely just a bit better built than most of the Belgian proofed guns I have seen carrying this W Richards mark. It also appears to have been proofed prior to 1887.
The finish on the bbls of this gun are long gone, but the spirals of "Real" twist are still quite evident.