Was the interior of the 504 specially made for the US-export? Normally these -ahem- strange colours weren't popular in Europe.
Europeans prefer black interior, especially black dashboards, which is unpopulat in America. so several European companies had created more colourful interiors fot the US market.

Sorry, but the colour of the Peugeot-interior looks horrible, a mixture between granma's underwear and apricot-mousse, which was thrown out again.