There is .midnam file for Apple's DLSMusicDevice, thus no patch names.
Here's a workaround I came up with:

Under /Library/Audio/MIDI Devices/MOTU, take the "Default Names.midnam"
file
and rename it and place it someplace else.
Then take the "General MIDI.midnam" file and save it as "Default
Names.midnam"
and change this line to read:

The downside is that any unidentified device will now have GM names,
but the DLSMusicDevice will then have the GM patch names.