I'll say 1968 because that's the year the company was founded. The brand was established the next year. It's complicated and also irrelevant.
What counts is the Ideal Kitchen, and you're looking at it. As the cover says: Dream no more, my lady! Because you come up with color schemes like this when you lose consciousness. Turquoise cheek-to-jowl with brown.
I bought this for a dollar at the antique store. Someone's mom kept it. Put it away.
I hope her dreams came true.