I was suspicious when the return address on the envelope was not the Board of Elections. Instead it was The Center for Voter Information. I set the envelope aside until I could evaluate. My initial reaction upon seeing the envelope was feeling increased mistrust of anything about voting coming in the mail.
Regardless, the form I received appears to be the correct one per the linked article, i.e not pre-filled. Some people received pre-filled forms which are invalid.
Even if everything appears to be correct, I’m going to print my own form, if I decide to vote by mail, and check the recipient address carefully.