I've heard, and read, several versions of this story (yes, I'm Swedish...), but I've never heard the 'multi-coating' bit before, and frankly, I find it a bit hard to believe. Single coating (state-of-the-art 40s technology!), yes, perhaps, but multi coating? Also, the super-wide Biogon in an SWC is an early 50s design, if I remember correctly, and a different design than the 30s Biogon (like the Contax 35mm).
Also, the 'original Hasselblad', Hasselblad HK7 (HK for Handkamera (yes, hand camera), by the way), wasn't a wide-angle camera. I'll try to post a picture of one below. This one was sold at a Swedish auction a while back, and was equipped with a Zeiss Tessar 135/4.5. It shot 7x9, I suppose on 70mm rollfilm. But, then again, I have no idea how much the HK7 differed from the German original.