Notice that the gun in question was made in 1981,,, not 1974. The stainless signature series guns were done at the end of the production of the MKI as mentioned above,, and then the MKII was introduced at the 1982 SHOT Show,,, I know,, as I was there to see a pair of 2 digit guns,,, and talked to Bill the same day.
And as mentioned above,,, the price of $600 for it is too high.