Re: matte finish
There are other factors that have a much more dramatic effect on the sound than the finish, such as the mouthpiece, ligature, reed, and the type of pads used. Just about everyone uses some type of reso-pad these days, but the size of the resonators some difference, plastic vs. metal, etc.
It is true that a gold or nickel plate is the brightest. A silver horn is slightly brighter than a lacquered brass horn and a matte finish (like the old Conns and Bueschers) gives it a warmer tone also. Rolled tone holes also provide a warmer sound. The resonation is best on an unlacquered horn, although in my opinion the benefits of the lacquer are more important than the slightly better resonation.