I don't mind a card that has writing on an otherwise blank back, especially when I'm able to obtain an otherwise nice card at a reduced price.
To the OP and anyone else who is interested, IMHO, the best source of info re the W575-1, E121, and related cards is the Old Cardboard article written by Rhett Yeakley, Net54's resident authority on these card issues. This article appears in the Fall 2011 - Issue #26 of OC Magazine (
https://oldcardboard.com/ref/BBC-ind...il.asp?id=1269). Unfortunately, the OC magazine articles are not available online, however, a back issue of this magazine issue can be ordered from OC's website.
Re the W575-1 cards, Rhett states in his OC article that "A common misconception is that these cards were 'strip cards,' but this is untrue, and the vast majority (over 95%) were factory cut and produced as an insert with a product. Essentially, these cards are blank backed E121 cards. The vast majority of these cards are found with blank backs, however they are sometimes found with a company name rubber stamped on back."
I have seen instances where TPGs have misidentified W501-2 cards as W575-1 cards. W501 cards were produced in vertical strips or rolls, hence the top and/or bottom border is very often a rough or slanted cut. The W501-2 cards do not have "G-4-22" and a card # printed at the top border like the W501-1 cards do, which is why the W501-2 cards are sometimes mistaken for W575-1 cards.