Yup! I found the diagram in the Manual again earlier this evening, and sure enough, that's what they did!
That's as good a guess as any, and there may be some truth to it. Not too long ago "Dave999" (sp?) in the UK (an Aussie ex-pat, IIRC) said this car should have P/S, based on the "700 Regal" trim level, but the option codes doesn't show this. However, Bazza told me (via text msg) that one of the codes has too many digits, which he believes signifies a "P/S Delete" car, so perhaps there was a mix-up on the assembly line that day....