I believe Chrysler and Ford used enamel while GM used lacquer generally. Lacquer just didn't hold up over time as well IMO without crack lines and seemed to deteriorate more readily due to thinner coats generally.
Neat photos. On a related note, anyone have any magazine print ads from Chrysler Canada? I only really look for 1966 Chrysler ads, but all of the 1966 Chrysler ads I see are from the US, except for this one. I found this scan of it online somewhere, not an actual hardcopy.