Retro Dog Riddle

Help!  A little off topic but you lovely people might be able to assist: does ANYONE have any idea when these were made?  I found them thrift shopping a few years ago, and yes, they are bonkers, and yes, my big beast HATES them, but yes, I LOVE them.  I'm guessing 1950's or 70's, they're made from plaster but that's all I know, comments very very welcome!  (Crochet skull bunting heading your way soon...) xxx