They made some patterns in SS in the 70's, but never the 83 whittler. In fact the first time a standard production 83 was made in SS was in 1999 when they reintroduced the pattern.
Any Case knife made with SS blades in the 60's and 70's will have the word STAINLESS in the main blade tang stamp - CASE XX STAINLESS, CASE XX STAINLESS USA, CASE XX STAINLESS USA with dots.