Mike that is an interesting point.
I have a somewhat similar issue with my rear end. It appears that my rear was hand stamped so after each character there is a space before the next. You can tell it is not a gang stamp. I have found 2 other rear ends now with the same appearing stamp, that were stamped on the same shift with the same method of hand stamp as mine.
*Unfortunately according to the "powers that be" they have said mine cannot be verified, because there is not enough examples that have been found to do so.
I think finding even 1 similar anomaly in addition to your own, where you can piece together what occurred, should logically be viewed as being a very real possibility. Also I am not sure how many similar "anomalies" would have to be discovered or come to light, for this to be verified.
IMO I tend to agree with the perspective that the cars were put together with human hands, and mistakes/differing techniques may have resulted in little quirks here and there. You are lucky you found another similar to yours for piece of mind. I cringe at the thought of guys thinking there car is not original because of some of these quirks, and changing them to conform to whats (currently) known.