Removing material on a gun is always a good idea.
But it's yours and you can do with it as you wish.
You obviously don't know Flitz...it's non-abrasive. At least the standard Flitz is for sure. I use it on my blued Smiths. So if that is all he used, he didn't remove metal.
And to the OP...your gun, do as you please. The only thing I don't like about satin/beadblasted stainless is that the high points become shiny from holster wear...but otherwise, it is a fine finish for a working gun. Polished stainless, though, is always beautiful. I have 4 stainless Smiths - two high polished, two standard. All 4 have been treated to a liberal dose of Flitz...but the two standards will never catch up to the shiny of the high polished ones. Congrats on getting the 60 again...