I believe this would be point, Where you should learn to make backups. Before messing around with scripts. if you dont know exactly what you’re doing.
Also i have used parts of flickcorp script on already configured RPi2. Which i found useful for me . And everything worked fine. Just to be on safe side. I’ve done backups of it prior to mess around.

I’m glad the script was useful lol have to add the title clearly says quick setup