If you read the comments to this post, you might have seen two interesting ones:
First, a comment from one of the women behind Knit Stix, Aleta Frost, stating that they had a design patent, that they expect to receive a utility patent, that their product was patented, and inviting me to contact her for more details.
Secondly, a comment from Charlotte, who used to have some of these old calibrated needles in her possession, so they were produced and the markings were sufficiently durable, contrary to my speculation.
In response to the first comment, I sent an e-mail to Ms. Frost asking for details and explaining where I found the prior art patent. She did drop me a note this morning to thank me for my continued interest, but I didn’t get any more details — she just said they’ve contacted their lawyers about what I wrote. (Understandable — if the applications were filed this year, they’d most likely still be unpublished, and you’d want to consult your lawyer before divulging information about an unpublished application.)