Could this be a Miller trigger? I know the shape of the trigger shoe is not characteristic Miller, but the LSR, depending on its appearance, may be Miller stamping. I am not familiar with the style of stamping on an original Lefever tang, but a good picture of the stamp would clear this up. The forward position is not common on the Miller, but there are some out there. My PHE Parker pigeon gun has a forward position Miller. Not all Millers are stamped "Miller" on the shank, but most are. Does Elliott illustrate the top tang stamping of an original Lefever single trigger gun?