I would say that M494 was a transcription error, although I have found it in the document that accompanies the new S/T and also in a previous article by someone from Porsche. If I remember correctly, M494 was Turbolook for the cars of later years, so in my opinion, M494 doesn't have much relevance.
+I thought so, now I don't remember where that information came from or if I'm mixing it up, but at the time, I couldn't find anything regarding 494 for these ciches