Yes and No...

Normally when you choose a voice to play within a piece of music, you must bring up the Instrument list which gives you many parameters...
STAFF NAME - INSTRUMENT - CHAN - PROG - GM


when you first launch this window you will be in a General Midi mode where you will only be able to access GM sounds. In order for you to actually access the voices of your particular Sound Module you must

1) click in the space and hold until you see the option of NEW INSTRUMENT...
2) this brings you a box that says INSTRUMENT DEFINITION
3) depending on which Midi driver you are using (freeMIDI or OMS)
at the bottom of this box there should be a box where you can choose which device you are attempting to access...
4) Next to that box, there is a space where you can choose the patch of your sound module...
5) at the top of this BOX is a selection where you can name this instrument that you have just created... Type in the name of the voice that you are using from your module...
and now hit O.K.

Now per the folks at Finale, the GM voices will still show in the column called GM but your voice that you created will now show in the Instrument column...