Much as it pains me to agree with Tony
(where's the fun in that?) I have never, ever, viewed the heads that are inlaid or carved into Northampton/Lehigh rifles as representative of Indians. Berks is a different story - a number of the heads I have examined on Berks rifles (as Patrick Hornberger mentioned earlier in the thread, primarily attributable to the upper Townships) are clearly meant to represent Indians complete with feather or feathers.
These decorative interpretations are worthy of a completely separate examination; let's not confuse the two.I think it is a
BIG mistake to view the representations of two distinctly different regions as the same. This thread specifically made note of the "Lehigh" area, by which most people mean the arms made in the vicinity of Allentown. All of these 'portraits' that I have personally viewed appear - to me - to clearly represent a woman (some of an obviously buxom nature...) wearing a Phrygian/Liberty cap. I have not, to date, found similarly-executed representations on any other object of the region, which if you think about it is surprising. Nor are their any surviving written reference to date; if there are any to be found, I suspect Professor Gordon will find them!
The closest thing I have found to compare to what is found on these Allentown-area rifles can be seen on the earliest US (i.e. post-War US) coinage:
(Poor quality scans, don't have much time at the moment)
What is interesting is that these early representations also coincide with the period during which the bulk of these effigies are assumed to have been carved/inlaid upon the rifles, i.e. the period immediately following the War, say approx. 20 years give or take.
Why Northampton/Allentown?
The earliest carved version of this head which I have viewed is found upon an unsigned and currently unpublished rifle which I would attribute - based on style, carved detail and furnishings - to John Moll Sr. Yes, an attribution only, but I feel an intelligent attribution based upon comparison with slightly later signed rifles. I believe the rifle in question dates to the period 1775-1785 and appears somewhat contemporary to the signed and dated Oerter rifles.
I am firmly convinced Moll was involved in the War effort ca. 1777-1779 when a very important gunsmithing/gunstocking/gun repair arsenal was established at Allentown. All of the men who signed rifles which feature this "liberty head" were men who have for any years been considered as prime candidates for having been involved with this arsenal. Furthermore, during this period of the War, the population of Northampton Co. exploded - following the evacuation of Philadelphia - and it became a crucial crossroads of men and materials necessary to the War effort. It also became a hotbed of patriotic fervor.
So, my personal opinion (
which is of course speculation) is that this representation originated as something basically akin to a 'club' symbol, something like a badge which developed amongst a small group of men in a confined area all working at the same trade at the same time for the same cause. The concept of the Liberty Cap or '
Lady Liberty' was an important anthropomorphic evolution of the drive for independence, was well-known throughout the colonies, and it seems to me only natural that much like practically every other object within the budding United States it would be interpreted via a visual regional dialect of sorts.
Everyone else's mileage may vary.