Also ... one last note and just interesting. The pictures of those on-piece (I could have sent much more) were sent to the same company in Mass. I assume that the receiving clerk at that company cut the corners off of all of the covers as they came into the company from all over the US.
How do u know ... u ask. Well I don't know 100% but on most/ALL of the ones that had partial address and wonky written address next to stamp or irregular cut on piece... had the following company for the to address:
H.W. Smith Manufacturing Company
Box 509 (sometimes Box 1264)
Worcester, Mass
I tried to research that company and find out what they made and why they received so many orders from across the US but the best I could come up with is some kind of fabric?
(the above is just an FYI/interesting--- that even though the on piece did not always have much or all or partial address, I was able to piece together (ex-Navy crpto guy) the "who" was getting most/all of the letter traffic).

So if any of you can add to that company's story ... let me know