Tim
Lower grades were built without wings. Later C grades dont have them.
I think your gun was sent back to Lefever for another set of barrels and they just happened to have a set of F grade barrels to put on it. This is not uncomon. Ive seen a B with Opt barrels.
Early guns seem to have a grade stamped on the barrels and later gun dont. I dont know why.
bob



lefeverarms.com