I imagine those would be in the public domain these days.
The quality of transfer on old public domain movies can vary a lot. Public domain classics sourced from old exhibition prints, Nth generation video, etc. are real cheap, but if you’re willing to pay you can get good restorations with lots of documentaries, contemporary stills, etc. I have no idea how much effort Warner Bros. is putting into this effort—probably little to no restoration, but if they’ve really opened the vaults we’ll get the best video transfers yet.