He stated in the article that he believed the box to be from a John Moll II rifle, and I would agree with him. I do not in any way think the engraving is that of John Sr. - i.e., the guy who was working in Berks ca. 1751 at least and thence to Allentown - and I am basing this opinion on earlier signed "John Moll" rifles with much more refined and competent engraving, as well as engraving remnants on two restocked guns with "Johannes Moll" inlaid barrels. John II and later John III do not appear to have developed the engraving skills of the old man, although attributing all these Moll rifles to respective Johns is still somewhat sketchy.
FWIW, I see it as a depiction of a rifleman: heels as mentioned above, a rifle w/ a box and what looks (to me) like a long hunting shirt. But then, I'm biased - I really don't buy the indian representation save for one or two rifles where a very clear representation of an indian was engraved or carved complete w/ feather.