OK, so now I'm going to ask the "elephant in the room" question:
Why in the heck would the factory blue a stainless steel gun.
To answer your question out of order..... Yes also offered a version of 686 with the "black". There are chemicals that react with the nickel in stainless steel to make it black. Not sure what Smith did to attain the color. Look in the Brownells catalog, you can purchase today. I almost bought one when they came out. I was still living in Virginia so late 80' or early 90's. As a possible answer to as to why they would do that, I'm not sure. I know S&W had put an ton of money and hope in the L frame. But 1986 the winds of change began with the FBI Miami-Dade shootout. From that point on the call for more fire power in law enforcement holsters was the rule. Semiautomatics and new calibers. S&W 1076 in full boar 10mm lead to the .40 S&W cartridge. Smith was beaten to the market with their .40.S&W by Glock's introduction of the G 22. Smith introduced their 4000 series .40s but it was too late. Sig, HK, Beretta Walther etc were putting out wonder 9s and .40 S&W guns. To salvage what they could of a shrinking revolver market, Smith had to offer something different. Stainless steel wasn't all that common back then. The.revolver crowd was used to deep.polished blue carbon steel. Now you you could get the best of both worlds... a blued stainless gun. That failed miserably for Smith. I remember seeing L frame revolvers being used as lost leaders to get folks in the store. That's why I thought had about buying a blacked out 686 new in the box for $350.00. Also remember that the milsurp market was in full swing. Surplus US M4 carbine bayonets were more expensive then the carbines they went on. It was wild back then. Hope that helps.