In some years the 2+2 was a trim level (on the Catalina in the US, on the Parisenne in Canada). In some years it was a standalone model. I believe for 1969 its actually standalone. It has its own section of the brochure and its own column in the technical specs, so it appears to be a peer equal to all of the other models, so far as I can tell.
Does anyone know though? And how it might have changed year over year?
I assume you mean 67-69, but the 69 brochure sure seems to track it as a separate model. The word Parisienne does not appear on the 2+2 page, which consistently calls it the "Pontiac 2+2".
In my GM Canada parts books, when decoding the VIN, for 67-69 it shows Parisienne 2+2. For 1970, it shows 2+2.
Yes, and both Parisienne 2+2 ('67 to '69) and 2+2 (1970) use the same body number or as they call it, Series Designation - 768. (Except '67 six cyl 2+2 - 767). Parisienne uses 764 and 763. So I'd say that makes them a separate model and not just a trim package or option.
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'68 Parisienne 2+2 Convertible Matador Red (Resale Red but not for sale).