Hey.
I know it's a while since you posted your original comment but it's an interesting observation.
It spurred me on to check my own car for the item you have described and low and behold, I have the same plate tag
So I embarked on a bit of research and after some time I think I have come to a conclusion...
Until 1969, Generation I Camaros could actually be found on production lines in Antwerpen.
The site fitted the sunroof option for example, of which the components were manufactured by a single German firm.
Other cars, destined for customers in Europe were shipped there to have the final touches added to them.
This allowed GM to avoid steep taxes and import duties which were levied against finished vehicles.
Vehicles which underwent this process do have distinctively different VINs though.
There will be no Ohio or California based digits such as 'N' but a 'GX' or 'HX' instead. These differentiating year of production.
As I said however, this all ceased at the end of 1968 to the beginning of 1969 when GM pulled the plug on production in Antwerpen.
Nevertheless a site office remained to handle orders and other European matters.
So why does my car, a Norwood built '76 model with no sunroof and yours, a Norwood built '79 model with sunroof, have the tag?
Simply put, it is because these cars were ordered directly from Europe.
Built in the states to the desired spec and then shipped to the European customer.
They would be emblazoned with the tag in question on arrival into the Antwerpen import office.
The link below sums it up quite well if I have made it sound a little confuzzling
http://www.camaros.net/forums/showthread.php?t=107186
Hope this helps!