I dunno if footage of this exists, as I searched it up multiple times now.. a few minutes ago. Anyway, to quote Wikipedia, "Promoter and first WWWF President Willie Gilzenberg appeared on Washington, D.C. TV in 1963 and declared Rogers the first WWWF World Heavyweight Championship; this was explained by Rogers having won a wrestling tournament in Rio De Janeiro, Brazil, although many doubt the authenticity of that tournament." I don't think there would possibly be footage of this happening, but knowing WWE, they have footage or photos dating back to 1963 I think. By the way, I'm not talking about the Rio de Janeiro tournament as that doesn't exist at all (it's fictional), but I'm talking about the announcement. I don't see any footage of it on YouTube, or DailyMotion or any other video streaming website... so, the existence of the footage of the announcement is unknown..
If this existed I would think it would have aired in one of their many documentaries by now, it's not the sort of historic event they'd just leave sitting in a vault. 1963 is very early.