Grade marking A though E began with the Barber & Lefever Guns. Not all Barber and Lefever guns have a grade marking.
Most all of the Nichols & Lefever are marked A though E.
After Nichols went off on his own he added a AA grade.
The Sidecockers were marked AA though E.
Lefever Arms Co. guns started out with grades AA though F. F grade only had minimal border line engraving.
There are also unmarked guns that we call special order guns. Special order guns can be a very basic to higher than an Optimus grade.
The next grade to appear want the Optimus around the 102xx range.
The next grade Dan added was the G or Ideal grade around the 14xxx range. The G had little or no engraving. The F by now had a bird or a dog on each side.
The H was added around 19xxx and was basically a G grade with twist barrels. As a lower grade was added, it seems like the rest of the grade were up-graded.
The Special Order gun pretty much went away when Dan left lefever Arms.
The DS and I grades were add around the 36xxx range. The very first one had cocking indactors, a dolls head, and twist barrels. The was quickly changed to steel barrels with not dolls head and cocking indactors.
I'm not real sure when if at all the 1000 dollar grade came onto the scene.
DM Lefever & Sons guns were built in the 0 excelsior, 9F, 8E, 7D, 6C, 5B, 4AA, 3 Optimus, and the Uncle Dan grades.
Variations of LAC guns
Cocking rods, 91xx-13xxx
2 piece, 12xxx-25xxx
Small hook, 17xxx-25xxx
large hook, 17xxx-73xxx
Push button, 91xx-27xxx
Dogs head, 20xxx-32xxx
Clam shell, 45xxx-73xxx
Thunb puah, 91xx-99xx
3 Barrel, 91xx-92xx
Double rifle, 94xx-11xxx