Schreck, Just my opinion, but I would think probably not by S Miller.
I've had 2 signed ones and seen several others, and to me the carving doesn't look done well enough. Also the moon inlay, though this inlay is most likely a replacement, the shape of the moon is too fat. Also, both rifles I've had have a patchbox hinge that goes all the way across the side plates, and not just the width of the PB door. Also, both lids were engraved. By the color of it, this lid might be a replacement. The toe plate also seems a bit short.
Other than that, it looks like a nice rifle for the right price!