Hi uptown47,
The problem is that there's no database available for Fruit machines! So unfortunately there's no chance to retrieve infos from database servers drop-down menu...but, you have the option to create a 'simple' database! By simple, we mean: a database which only lists the games from your folder...and I think that it is exactly what you're looking for!?
There's indeed a video tutorial covering this aspect here (beginning at 00:23...but the link should get you there directly):
https://www.youtube.com/watch?v=D2_DdYwks9M#t=00m23s
If I understand you well, you then want to edit the 'description' name (by opposition to the 'filename'!)
ATTENTION: you CAN'T edit the description name directly from within mGalaxy_Runway!
Actually, the distinction between 'description name' and 'file name' is due to MAME, where you clearly need the description name for the rom file!
For other systems, the description name and file name are identical! (for now!?)
What you'll have to do is to edit the 'xmlout.xml' file directly (this file is in mGalaxy folder > Data > UserSystems > 'the name of the system you want to edit' > xmlout.xml) and change the description name there!
ATTENTION (

): be sure to have a unique description name! I can't test it now from where I am...but I think this is preferable not to share the same description name across different games until I can check that mGalaxy wouldn't crash in such a case!!
Hope that it'll help!!