The opening to The Flintstones is iconic, but a generation of viewers had only known the 2nd opening, which was attached to the syndicated prints for decades.
Many hadn't even seen the "Rise & Shine" opening until the 35th anniversary special in 1995.
Cartoon Network and Warner Bros restored the Rise & Shine Flintstones opening to its prints in 2000 just in time for the 40th anniversary and the inevitable DVD sets that would be released later.
Incidentally, The Simpsons, a series that has become the true successor to The Flintstones, homaged the "Rise & Shine" opening in their credits, and viewers who didn't grow up seeing it in syndication never realized it.