Looking at the 1861 directory for Birmingham, there were lots of Dixons...everything from shoemakers to clerks. None were listed as gun stock makers. Doesn't mean much though. Is it stamped in between the two brass escutcheons by the lock plate screws? It could be the lock maker. Sometimes Barnett put their stamp in that location. I know that was the case on some Tower marked Enfields that were part of an early shipment aboard the Bermuda, if I am recalling that correctly. In other words, it could be "setter-up" who filled the contract.