Official Super Mario Maker Thread - Mario Maker for 3DS has been released?! Ok...

[Samus Aran]

TruckOSaurus said:
What happens if you edit a course you've already uploaded? Does the stage keep the same code (and stats) when you upload the updated version?

Nope, it's a new code. It's understandable because people could change a good level into a crap one all of a sudden.