1966 Topps Rub Offs - Series?
 

Curious if anyone knows which series included the rub-offs? I assume all didn't as one of the wrapper variations doesn't mentioned them.

I searched YouTube for any pack breaks but only found a couple cello busts from series II and IV, and neither had the inserts.

Series 1 and 2 in rack packs had them. Beyond that, I don’t know.