This is indeed a hot dog vending machine – installed later at Grand Central Station, Manhatten, New York, USA.
There must have been at least one other model – perhaps the production model – and seeming without the ‘Radio Chef’ banner which perhaps could have been confusing or scary for customers!
Remember that the microwave technology these machines used didn’t arrive in the home until around 1967, though they were used commercially before then.
They may or may not have made the prototype – and definitely held the rights to microwave cooking technology – but it’s probably more likely they licenced a vending company to make the actual machines.
Keep checking back for more fascinating blasts from the past!