There were definitely some very gaudy guns in central Europe in the 18th C. If you look in the collections of some of the castles and royal armories you'll see some guns - fusils, fowlers, pistols, and yes, jaeger-type rifles - that have this approach. I have a book of Peter the Great's collections, and some give this gun a run for its money!
In the mid-19th C - the end of the longrifle period - there was a school of gunmaking that went hog wild with German Silver, well into what I consider the realm of tastelessness, although it's amusing as a study of folk art (See chapter 18 in Merrill Lindsay's "Kentucky Rifle" book). The gun in this ad reminds me of some of the feel of those guns, but the style of the castings (as the maker/seller states) is 18th C. European styling rather than mid 19th C.
If I was doing an 18th C. European style fowler, in walnut of course, I'd consider that entry thimble. I think its cool.