Can't embed. But here they are in their full Ford Era glory, sideburns and all!

Lee is promoting the publication of Origins of Marvel Comics. The date given is October 22, 1974, which fits in with Origins' release. The Kirby clip is from a couple of years later.

Kid at 1:30's got it together. Some early cosplay at 3:06.

Found via the awesome Marvel Comics: The Untold Story tumblr, curated by the author Sean Howe. You need to read this book, if you haven't already.