This is a pretty good explanation from the folks at Harrelson Trumpets. The talk about bare brass, silver plating, gold plating, and lacquer and the way each can affect tone. This is often discussed among brass players and the answers, according to Harrelson, may surprise you. Note the discussion about stripping an existing finish and also the fairly clear answer about lacquer. It does not cover a satin (sandblasted) finish or a brushed finish, and does not mention if any difference in prep for a given finish might affect metal thickness, but there are some good basic concepts here.