Sorry about the 591 goof - a typo for 501 and I bow to your position. If your SG is tagged 531, then so too must the Mistral be.
Those prices on your web page must be not be in US currency.
The currency I reported was taken from a CCM Dealer's Parts and Price book. Perhaps I should have pointed out that the currency used for a Canadian Cycles and Motor Company parts/price manual would be in Canadian funds. Of course, what that would mean little since I cannot remember what the exchange rate was at the time.
I must admit that I am surprised to learn that CCM bicycles were sold in the US. Anyway, sorry to mislead and, once again, I do like your bike.