[Zubersoft]

No, as the SongID field is saved in the database as a number and is not designed to be an alphanumerical field (all of the UI components are configured for a number as well). The field is not a generic metadata field (although some users use it that way without understanding the impact). That field changes how song matching works when importing/exporting .msf files, when using the library sync feature or when using the "Connect Tablets" feature. If working with other musicians where you want to sync libraries or share songs, it can be very dangerous to populate that field without understanding how it will impact those features. 

The custom field is designed for exactly what you are using it for, so I would recommend continuing to use that field, as you can enter anything you want in it. 

Mike