What was it signed as heading north at exit 36 (where the mainline E6 turns off)? GMSV has it as E6 with solid border, hence why I included the route.
I've checked GMSV. There are also some E6 signs with solid border on "Holtermanns veg". If I'm not mistaken, pics were taken in April 2010.
The situation is different today. I think the big sign on exit 36 displayed "Center" only without any number. Afterwards, there was definititely no E6 sign with solid border. I spot just one with dotted border on the sidewalk and green 706+E6 numbering on the big direction signs with dotted border...