It's not a Sonnar design, it's a Gaussian type. The only "normal" 135 film lens of the Sonnar design was the very early preset Takumar 58mm f2.
https://imaging.nikon.com/history/story/0002/index.htm
Yes, a fairly odd-looking gaussian in profile, but definitely a 6-element variant on the double Gauss, as the Biotar before it.