This just arrived in the mail.
The ebay seller wrote " A few are marked Greist. I did not see any marked Singer."
Which is correct - except that the needle threader is stamped Singer. Interestingly - the box has the holders for a different clamping style of foot than any of those included with it.
I needed the back clamp hemmer foot and the quilter foot to complete my third set - and this was cheaper than buying those two feet separately. Though I'm still not sure why I wanted the third set (they are all different) as I only have two back clamp machines . . . I'll blame it on the SMAD.
if you are curious, SMAD stands for Sewing Machine Attachment Disorder. I've got an acute case of it!