There are no current or past technologies that make stainless look like a blue carbon steel firearm. If that is the look you like, then you need to buy a modern carbon steel firearm like these model 27s.
Smith and Wesson has been using IONbond for more than a decade now. The IONbond finish that S&W uses is a black looking finish, not blue.
I am not aware of the folks at IONbond offering a polished version. I just reviewed their website again and see no mention of this option
IONbond does looks different if applied to a surface that was prepared with a brushed vs. matte vs. polished finish prior to application. Is that what you are referring to?
This Pinto 627 is about 13 years old. The 627 was prepared with a more polished finish while the TRR8 pictured below it was not. The difference is not that great
All of the Night Guard revolvers plus the M&P revolvers use the IONbond finish to match the cylinders to the Scandium frames