Jim,
Did you read through my notes? There is a progression in the symbols that makes some sense. Of course, you have to accept that such symbols are meaningful to some people and that they would include them in their art work.
I was raised in the church and am quite familiar with such symbols working their way into art long before I studied such things. After all, have you ever been to Sunday school as a child? You are taught to include many religious symbols in your art work. I expect that most everybody in 18th and early 19th century America had such an experience. Also look at the timing of the three Great Awakenings and look at what was happening in longrifle design and decoration at those times. I do not believe it is unrelated.
Also, as you study art history, you see symbols from the cultures' religious life sprinkled liberally throughout artistic works both directly and indirectly. As I mentioned, I have included such symbols in my own art work from childhood. It was part of my education in the culture in which I lived. It would never occur to me NOT to take such things seriously.
If you study art history, as I have, the presumption among scholars for centuries has been that art work is influenced by the most powerful forces in peoples life; most notably, reproduction (life & death) and religion (life and death). In fact, they are inextricably related.
If you contact Mr. Kafka, he is a KRA member and former president, I am sure he will point you to numerous resources that would address your questions.
Now. All of this being said, I don't believe most gun makers had any idea what the symbols there were using meant or were supposed to represent. You see this all the time as carving and engraving designs that were once quite clearly identifiable devolve over time into an highly abstract version of the original idea. One that I particularly like and have used many times in a more literal way, including on that rifle I completed about a year ago with the bold silver wire, is the Lilly of the Valley. The Lilly has long been associated with birth and rebirth. Why do you think churches are filled with them at Easter? If you look at the early Lancaster trained gunsmiths, many Moravian or trained by Moravians, you see a very clear representation of the lilly in the carving behind the cheek piece. This motif was brought to Winchester,VA by Simon Lauck. His early guns and those of his contemporaries showed this motif very clearly and identifiably.
As you move through time and south along the Great Wagon Road in the Valley of Virginia, you still see this same motif all over the place; but it becomes more abstract with time and distance until it bears little resemblance to the original motif that spawned it. and has probably lost all symbolic meaning to the maker. It is has become just the corruption of a design used by a master or contemporary whom may not have known the meaning either. That doesn't mean it didn't or doesn't have meaning. It is like the old philosophical question of if a tree falls in the forest and no one hears it, does it make a sound. The factual answer is that it does. The philosophical answer is not so clear. You, I take it would say no. I would tend to say yes it does. Both of these positions seem somewhat ironic to me with regard to rationality vs faith.
I understand your reluctance to engage in such thinking. Both my primary mentors were/are not religious people and had a very different view of such things as myself. Carving on my rifles that they would interpret as just a regurgitation of original designs and motifs have considerably more meaning to me. I, like Mr. Kafka, see my work as the result of God given talent and insight. My guns are a creation of God with a soul of sorts, and I am just the instrument. I genuinely believe that I am only able to do what I do through the power of the Holy Spirit. My carvings and wire work behind the cheek on many of my rifles represent to me the death and resurrection of Christ and the ultimate destruction of Satan's power on earth. If I believe this, why is it so hard to believe that some gun makers two hundred years ago might have believed this.
This idea of art having meaning is so ingrained in the historical idea of art that that is what you are taught at art school. I even rebelled against this a bit myself, only to later fully embrace it. In the fine art world, ART is not about design or aesthetics, it is about meaning. ART is supposed to be about stretching human thought and awareness, not just making something beautiful. In fact in art school and the fine art world, beauty for beauties sake is looked down upon. Not just that, it is ridiculed. You need to spend some time in art school critiques to understand how brutal the criticism can be. The point is that in every artistic tradition of which I am aware, art and meaning go hand in hand, like ying and yang. It is assumed for if it isn't there, it SHOULD BE there.