Not sure if this rifle has been brought up before and my apologies if it has.
I found this when doing google searches on flintlock rifles with symbols for the discussion on Shreck's ancestor's inlays.
Once loaded, left click on the image of the rifle four times and no doubt many of the Bretheren will easily notice the Masonic Symbols.
http://www.aagaines.com/guns/wheat.htmlHope you enjoy it,
Gus