I had already seen the 175 and the description lets say has a couple of real howlers in it! Price is very ambitious!
The SC is a wide case bike, not a narrow case one. Wide case not available before end of 1968 - so good chance it is a fake. World expert on these is on holiday for the next couple of weeks, but back before the auction.
I get the feeling that this auction may contain more than a few wronguns.