Tinstar, There is an excellent CD available which will help you determine the differences between the Bucks Co. guns and those made in the Lehigh Valley. Actually there is quite a bit of info available on the Lehigh Valley guns verse very little regarding the Bucks Co. examples. The CD mainly applies to Lehigh, Allentown and Bethlehem. Once you have the examples from the CD firmly entrenched in your mind you will have to dig thru the various available books to find examples of Bucks Co. guns by Andrew Verner, John Schuler and George Weiker. The best source is George Shumways 'Rifles of Colonial America Vol. I'. He devoted 20 pages to Bucks Co. and shows examples of the three Bucks Co. gunsmiths I make reference to.
The CD is available from the Kentucky Rifle Foundation and advertised on the KRA web site. You can order thru the mail or pick up a copy at the various affiliate KRA/CLA local shows depending on where you live. Good luck, HIB