Proof it exists?
From The Lost Media Wiki
Hi. I found this https://archive.org/details/Monsters_of_the_Movies_004_Curtis_Gambit-Woodman-Mal32/page/n43/mode/2up?q=Black+ripper+saletri on archive.org
The magazine this was published on is from 1974. It seems they would list movies that were in production. Probably not useful, but still an interesting mention from somewhere else that isn't Variety.