The "A" prefix up near the forearm first came into use in the 1916/1917 era.
If any deluxe guns are found with extras, then that particular gun was assembled from parts on hand, left from the original Marlin Firearms Company that was owned by the Marlin family. I have seen some deluxe guns with letter prefix serial numbers, but not many.
Due to the increasing cost of ammunition, there be no warning shot!
The growing federal deficit = generational slavery to the national debt.