For Steve and everyone else:

I got in touch with the University of Glasgow archives on:

dutyarch@archives.gla.ac.uk

The Army & Navy became a chain of department stores which fairly recently merged with the House of Fraser, a Scottish chain of similar stores. Their records show when the gun was taken into stock, who the actual maker was and also when it was sold, which in some cases was two or three years later. Might be useful with your BATF rule about 'made before 1898' [from memory].