Lefever does not follow any hard and fast rules. Ejectors were often not marked on the watertable, but on several extractor guns they were marked with an "E" that was clearly done by the same stamp that struck the first grade. So you have a EE, FE or GE, which is in fact a E,F, or G grade extractor gun. Serial numbers often seem to fall out of order. Early numbers with much later features. Features often tend to change over a range of numbers instead at a hard and fast line.
On the plus side Lefever never lowered fit and finish like Fox and others did towards the end. They improved the engraving as time went by and when the need to have a lower price point gun got too large to resist they created the H, I, DS grades, ect... Their wood selection was quite good and some of thier stocks even on the lower E, F and G grades is exceptional.
I just wish that they had made another 60,000 so we would have more to look over and choose from.