Dan-You are absolutely correct on the considerable age of the use of animals and mythic figures for gun art. The best example that can be called to mind here is the Christian Oerter
1776 rifle with the fabulous griffin on the cheekrest side. Far as I know, this is the earliest dated such gun. The lion and the dragon were also used around the same time.
A bit later, Nicholas Beyer made a celebrated rifle with an evil looking bird carved on it. And, John Gonter made a rifle with what appears to be writhing snakes carved on the backside. It was recently shown on AspenShadeLtd.com, and was for sale. Still and all, these pieces are great rarities given the vast number of rifles that were made.
So, carving or patchbox, neither are fanciful, but are grounded in solid examples of some pretty fine old rifles.
Dick