Fred, depending on how you interpret the Vi-shooter data and associated dates you could be correct. There is also likely a difference between "end of production" and "end of inventory". Even if the change order to eliminate the notch was approved Jan 1, I would expect a fuzzy transition due to WIP and existing inventory. In this particular case of the ladder sight that is prone to damage, significant inventory was likely available (some speculation on my part for sure) for much if not most of 1918. That would make your assertion very plausible.