The answer is yes.
The UK concessionaires were left with many unsold e9s. They decided to update them with a vinyl roof which was a short lived fad in the mid 70s. Blue was a popular choice particularly with chamonix paint and was allegedly used as a nod to the then BMW motor sport colours.
I am in no position to disagree with your UK vinyl assessment, since the majority of those few vinyl'd E9s seem to be right hand drivers. Considering the relative scarcity of E9s and E3s, any two similar vehicles might arguably establish a bonafide trend.
I distinctly recall, years ago, having seen a left hand drive, black E3 with a black vinyl roof outside of a US Airport. It may have had diplomatic tags. I also vaguely recall seeing a yellow (not golf) left hand drive E9 with a dark vinyl roof on the interstate in the Southwest US. Since the addition of a vinyl roof covering is a "relatively" simple procedure, it could have been for two-tone cosmetic appeal (
taste being in the eye of the beholder), or as a cover-up for hail damage, rust or some other cosmetic blunder.
Most of us have probably witnessed many other E3 and E9 eccentricities. I am pretty sure I have seen a lowrider E3, an E9 with wire wheels (Dunlop?), an E9 or E3 with odd rectangular forward lighting from ??, and an E3 with a rear spoiler that might make even a Plymouth Superbird blush. (T
he Bavaria's trunk spoiler looked like it could substitute as a scaffold for second-story work.;-))
http://e9coupe.com/forum/showthread.php?t=2701
Gratuitous pics from Süd Afrika:
https://drive-my.com/top-blogi/entry/collection-of-bmw-e9-cs-coupes-from-south-africa.html
And Oakland, CA.
http://californiastreets.blogspot.com/2014/04/oakland-street-sighting-1967-bmw-2000cs.html