Here's the OP's second option with fonts modified to more closely represent Signature Plastic's font size and placement.
OP absolutely nailed the theme with the colorway and I could appreciate it but it wasn't something I would have considered buying.
I think Pinecone's second mock-up refines the concept into something that probably cannot be improved upon unless novelties are added.
The problem is in designing novelties that don't infringe on Hannah-Barbera's copyright. Scooby Doo's dog tag would be a great novelty for the OS key but probably can't be used. I think Mystery Machine would be a great name for this set and, if that is the OP's intent, he should change the title to reflect that. Yet, as good as this looks on the screen, I can't help but wonder if it would be too colorful for a keyboard.
Also, OP (admgc) of Green Screen was gone for almost a month before coming back and resuming work on his set. With so many key sets in the pipeline, there's no need to race to the finish line.