Hi again !
Thanks for your comments.
As mentionned, the photo is taken from a book dedicated to Karmann. I think the year should be 1971-73 maybe, and they are all euro models.
Concerning the location, I think it's the Osnabruck factory, because on the center of the photo, you have a tiny signpost marked "BMW".
This implies that in this plant, all assembly lines may not be BMWs'.
Am I wrong ?
In any case, and after more than 25 years collectioning Coupés book, this is the only photo of assembly line of coupés ever seen .
And it's a color one !!!.
best to all