Hi mate. It's just the Smile no coo version of the Hong Kong figure from late ROTJ period.
There are three Kenner factories that made Zuckuss (as well as Lili Ledy in Mexico). The two HK variants were made by Smile and Unitoy. The easiest spot on the back is that the Unitoy figure had circular epms on the back of the knees and heels.
Smile did a no coo version, and the moulds travelled from Unitoy to Kader and they also made a no coo version with epms. The moulds then travelled to Lili Ledy.
Hope this helps.