Perry Mason does a plagiarism case (sort of) in The Case of the Promoter's Pillbox

In this 1962 episode, one Herbert Simms (played by Linden Chiles) is a pharmacist who aspires to be a screenwriter. He conveys a script for "Mr. Nobody" to producer Charlie Corby, who takes it, without crediting Simms, to use as a TV pilot. A clear case of plagiarism. However, in this plotline, the plagiarism is an afterthought to Corby's plans. Corby is funneling production money from "Mr. Nobody" to his own company, to make a European film, and has no intention of finishing Mr. Nobody. Assuming the 1975 copyright law applied to this 1962 episode, can one make out a case of copyright infringement (rather than merely asserting plagiarism)?

The episode is notable for the fictional Perry Mason proclaiming to know the real Rod Serling, who will help the fictional Simms. Separately, one gets a glimpse into Perry Mason's law school life, wherein he was helped by the mother of Herbert Simms.