The price was on the Smith and Wesson site, I think there were a few choices. I think that if you get it done the factory is the way to go. Keep the receipt as proof that Smith and wesson did the work.
Others will tell you that it takes value away from the gun.
The price paid for the gun added with the cost of rebluing will not equal the true value of the gun.
In other words, It usually does not make economical sense to reblue.