Here's a 1979 FAMOUS MONSTERS mail order advert for BUCK ROGERS IN THE 25th CENTURY toys and pre-assembled model kits (isn't that just - errm - a model?).
Note that the Mego Buck figure had already sold-out. But they probably found themselves stuck with a warehouse full of the (barely seen on-screen) Draco old-man figure.
I had the Twiki figure when I was little. Biddi-Biddi.