British officer's blunderbuss pistol

[Jim McDougall]

Interestingly, here is a Ryan & Watson (Birmingham) pistol with the attached bayonet. They worked 1780-84. Waters got his patent for this in 1781.
Just interesting context.
Their name is on the lock in large block letters.
Wallis did not begin working until 1807 according to official records,could he have apprenticed before that and perhaps made this pistol?