I think you are asking about the approximate date, and it is mid-sixties. Pioneers in the development of the skins as an appetizer include the Prime Rib Restaurant in Washington DC, R.J. Grunts in Chicago and the TGI Friday’s chain out of Dallas Texas.

While reading about Richard Melman, creator of R.J. Grunts, I found this quote in an article published in Nation’s Restaurant News:

Not surprisingly, food is a key source of creative inspiration for the company.  Melman maintains a hands-on approach to menu development – the test kitchen is just 25 yards from his office – and he finds ideas in unexpected places.

The inspiration for the potato skins at R.J. Grunts, one of the first restaurants to offer the now omnipresent dish, came from a radio story about sailors eating the vitamin-rich skins to ward off illness while at sea, he says. “My brother relayed the story, and I said, ‘OK, let’s monkey around with potato skins,’” Melman says.  “I’ve always been a person who pays attention to what people say.  It usually leads me to the new ideas I’ve tried.”

Here are some updated photo ideas for potato skins: