Well... I understand your reasoning tsmgguy, but there is a problem with it. The earliest Harpers Ferry muskets (not rifles) had locks dated "1801" (a very few examples still exist, 3 or 4 as I recall) but HF manufactured no muskets until, IIRC, mid-1802. They were, however, making locks and musket furniture (bands, triggerguards, butt plates, etc.) in 1801 and the locks date represents it's manufacture date, not necessarily the date of the entire musket. The same holds true for the rifles - a lock says one date and is accurate for the manufacture of the lock, not the entire rifle. The original Harpers Ferry records are needed to make any real determination. And, despite Lt. Jones' aforementioned efforts in 1861, that may be possible.... More later.