7mm pinfire, unknown date

Maker: unknown

Caliber: 7mm pinfire / 7mm Lefaucheux

Date: unknown

Status: Original condition, sold

This is a fine example of a well made 7mm revolver. Clearly better made as most build in Liege, but were this is made, when and by who is unknown.
There is only one mark, a B in a square.
Without more markings it is difficult to identify it's age and maker. I would be very pleased to know more so anyone who can give me more information pleas do so.
When I received it there was some surface rust and most of the original bluing of the hammer, screws and trigger was gone. It was completely dismantled, cleaned and the small parts that were blued are re-blued by heat.
The only marking
Little rusty
Clean and crisp