A quote from Chet15 at RENE . . .
"There were a few made, probably less than 100. At the time Ruger was having a tough time keeping their steel straight, mixing stainless with chrome moly, so there were a few different combinations of SA's that were made by mistake.... stainless Bearcats with blue barrels etc. You wouldn't know what material it was until after it came out of the bluing tanks. So in the case of the stainless .327 with blue cylinder, some chrome moly stock got mixed up with their stainless cylinder stock I presume.
"There was also a stainless Super Redhawk with a blue cylinder.
"A lot of that stuff went through Cabela's who has been the distributor for several years for oddball stuff and Ruger's "used" guns.
"If I remember right, it was about the time Ruger went to their new hierarchy and there was a lot of employee turnover."