What territory footage is public domain?

[Bix]

Recently I noticed that a lot more non-public domain and non-Creative Commons photos had shown up on Wikipedia, including promotional photos from old TV shows. When I clicked on one of the photos to see its info page since it didn't seem like something they'd classify as fair use, it was explained that since it was published between 1923 and 1977 without a copyright notice, it was public domain.

 

I googled and found this page that's on Cornell University's website. For our purposes, the important part is that from 1923 to 1977, anything published without a copyright notice is public domain, and from 1978 to March 1, 1989, anything without copyright a notice that wasn't registered in the subsequent 5 years is also public domain.

 

So it occurred to me that there's probably a fair amount of older American wrestling footage that qualifies. Memphis at least didn't run a copyright notice (either nothing or "produced by" Championship Wrestling/Jarrett-Welch Promotions/Jarrett Promotions/Warrior Sports) and I doubt they registered any of the footage.

 

Quickly checking some full shows I have on my NAS, these, for example, absolutely don't have copyright notices during the show closing:

 

Through 1977:

"Wrestling Champions" from Chicago (Fred Kohler)

IWA (Einhorn)

Wide World of Wrestling (Knozville, John Cazana)

 

1978-3/1/1989:

Memphis/CWA (A-show and B-show)

Southwest Championship Wrestling (the USA version, no less)

Mid-South Wrestling (but only some older shows)

 

So...someone explain to me if there's any reason why the first set wouldn't be public domain, and how reliable the official copyright office site is for finding registrations from the second set? It seems unlikely to me that they were ever registered, so shouldn't this stuff be in the clear?