I have researched further into this puzzle and found a bit of a minefield. You are correct about it's manufacture by SAAB's military section. I had Tjorven as the company who designed the Post office van section. Not long into the project the Swedish Post Office seem to have rejected the design and it then was taken up by Electromotion. I don't think it's known how many vans were produced but they became bankrupt and that seems to have been the end of it. If you can add any more I'd be pleased to read it.
One point for you.