I think I remember Jack Webb pronounce it in the French way in a Dragnet radio program. I bought all of the Dragnet radio shows for some bargain price on Audible a few years back and listened to every one. I even started the "Terms Which Have Disappeared" thread based on something I heard in one of those shows.Like sedan, a term usually seen only in auto press reports for the most part.
I know in the UK these terms are more widely used and understood, "motoring" being not just transport there, but a fun activity for many.
And "coupe" is pronounced the proper French way, "koo-pay" with the accent aigu over the e. Not the North American "koop".