Looks like a generic lock and "Riddle"could be a hardware store at one time or even the gun maker who made his own locks.
My maternal grandfather bought a general store in Roane County WVa in the late 1890's and it had a barrel full of locks that
had NO name on them and they were 25 cents each.He still had them when he sold the store and moved to Huntington WV
where we now live.Few American muzzle loaders had a quality lock as shown recently here,They were functional ant nothing more.
Most if not all locks now available are better than any of the locks seen on long rifles when they were in common use.
Bob Roller