My friend has an Alex Henry that looks to be it's twin could it be built by Alex Henry ?
You will see this often with British guns. Rocketman is on the right general trail. When the two guns in question are from well known London or provincial makers, it usually means that they were "bought in" from the same trade maker. This was an extremely common practice in the British trade, and ranged from parts as Rocketman suggests, to complete guns and rifles, ready for sale. The latter was a much more common practice than conventional wisdom has it.
I've been researching the Birmingham trade makers for some years. Although my research is concentrated on double rifles, it's still illustrative. In my database, I have two double rifles, one from Gibbs and the other from Henry. These rifles are identical except for caliber. Both are Webley PHV-1 Models, and both bear Webley serial numbers from the same period on the barrels. Also, both guns were clearly finished by Webley, not the retailers.
Gibbs generally numbered those guns built for them by others with a "B" prefix, but this is not entirely reliable. I've found "bought in" guns in the general numbering system as well.
