I take it from the other post that you are evaluating the demo of Finale. So I may have been mistaken in informing you that the mutes are present. Finale's set of GPO is slightly less than full. I checked the instrument list and did not see a mention of brass mutes. They may only be available in the full version of GPO. Finale users please feel free to correct me on this if I'm wrong.
As for sample patch, it is an unofficial term (and somewhat redundant) to specify which instrument is used. To play back sounds, Finale (and most other music programs) boots up a whole bunch of little wave files. These are referred to as samples. A patch is a general term to specify the instrument you want to play, and is a compilation of one or more samples of that instrument (samples varying by tone,volume,etc). So yes, Finale will have patches (the demo will too).
yes Reegs i am looking at it. it is like a wonderful very complex toy right now, because all my experience is writing music with my hand. i think i will send a message to finale and ask if the mutes are present in the GPO that is included in the product. mutes are used all the time. if not there, that's kinda awkward. thank you very much for you educating me