Stainless steel makes a great base material for standoffs because of its strength, corrosion resistance, ease of maintenance and natural aesthetic appearance. The aesthetic appearance that customers see is not the way the materials shows up at the shop though!
Generally, when working with stainless steel, manufacturers will offer mechanically applied finishes, rather than coatings, because the coating would likely be less durable than the material itself, and you are already paying a premium for the material. The two most popular mechanical finishes are a brushed finish and a mirror polished finish. A brushed finish is quite simple and is accomplished by applying an abrasive to the outer diameter and then blending the finish with a lighter abrasive such as a skotch brite. Sometimes if the stainless round is pitted, the manufacturer will take a .010” skin cut to the diameter to remove any surface imperfection and have a better starting point to save time finishing. Brushed finishes are generally accomplished on a lathe but another alternative would be to center-less grind the material.
To enhance the finish to a mirror polish, you effectively need to make the surface even smoother through the use of increasingly higher abrasives and then polishes. A mirror polish requires quite a bit more time than a brushed finish because rather than having the finish applied at 1 or 2 passes, a mirror polish can oftentimes require 7-8 handlings.
The picture below shows stainless steel standoffs with brushed and mirror polished finishes.
One thing to be careful of when specifying stainless standoffs is matching hand finishes with mechanical finishes. Stainless steel trim in architectural applications is often made from mechanically polished stainless steel sheet, which is entirely different equipment than what is used in finishing stainless steel standoffs. The specifier should be conscious that these finishes will not identically match.