Hell, the silly GR "rules" didn't even exist in Gene's mind until after the show was cancelled and Franz Joseph came up with the Saladin/Hermes/Federation odd-number engine designs in the SF Technical Manual. It was more of an FU to FJ to de-legitimize his work from a licensing POV than anything actually tied to the technology within the franchise. It was all a licensing pissing contest, from start to finish and, somewhere along the way, it became canon.
Edit: Ex Astris has an article about it with nice example illustrations and TrekPlace has an article at how the "rules" were specifically tailored to go after FJ's work.
Edit: Ex Astris has an article about it with nice example illustrations and TrekPlace has an article at how the "rules" were specifically tailored to go after FJ's work.