Then there's this Christian Oerter guy in a tiny shop away from any population center. For some reason customers far and wide found him and his rifles. Why did young Mennonite Martin Barr from outside Lancaster (far away) have Oerter stock a rifle for him, when fellow Mennonite John Newcomer lived close by, or with Dickert and other fine makers in Lancaster right next door? Scott wrote a great article about this letter, and what it might tell us. It is available from the Kentucky Rifle Association.
Young Oerter's work was perhaps special, and he signed at least some of his rifles. The letter he wrote to Barr shows pride in his work. I think customers then as now knew good and special work, and if that's what they wanted, they found their guy.
The design of carving on well known gunsmith's work is easy to identify, and varies by maker and location. We can see when an apprentice learns his master's style - Beck and Beyer for example, and later the apprentice sets up and takes the work in a slightly new direction. Or when H Albright or A Schweitzer move to another area, and change their design. It's certainly possible that someone in a particular shop might become a fine carver or engraver. All these masters we enjoy had to learn to draw, then carve. When talented enough they may have assisted on some work, but it does not seem likely to me that some master carver would go from shop to shop or area to area and know how to carve the local master's design. I've not seen any indication of this approach in the research to date. A young man would go on his Wanderjahre to another master, to broaden his exposure - like a journeyman. I am thinking he would learn from the new master, and turn out work that fit that location, though perhaps contribute ideas and skills.
Beyond carving, overall level of decoration and quality of design and execution counted. I agree there were plain rifles, and I have always enjoyed them. Architecture is the basis of any fine rifle, or as Allen M says, inside every great rifle is a fine schimmel.
These questions from new students, collectors and researchers keep our eyes open for new detail. Bob