As threatened last time, another new discovery awaits today buckaroos!
As verified by the Topps Vault, a handful of sticker versions of 1965's Kookie Plaks have been showing up on eBay of late:
It's really impossible to tell from the scan but that is a sticker and the copyright on the front would indicate there was no printed back. I wish a scan of the sticker back was available though.
The certificate of authenticity makes it quite clear what it is:
Kookie Plaks from 1965 are quite similar in appearance to the above sticker:
Similar but note the sticker has a T.C.G. copyright line on the front while the plak does not. The back of the plak shows us the copyright and also that is was mailable:
That back does not go with that front by the way. Jack Davis did a lot of the artwork for the set but it actually was a creation of his circa 1959 as Kookie Plaks are just reissued Wacky Plaks from that year:
Again, not the right back for this front but the Wacky Plaks back has the copyright and is the template for the 1965 reverse.
Pretty wacky, huh?