Terry of TandTrepair.com said the best information he could find was that it came with the flower stitch attachment and the dealer accidentally gave me a set. He said he didn't remember anything about it, but he was in the shop, not the sales area.
I understand that finding that answer took him a while.
I also finally got to post on the Singer Slant group on Yahoo. I don't have any answers yet. If I get a different opinion from them, I'll let you know.
So, basically, I don't need them and they won't stop the growl in my 778.
bkay