First off, this is probably the least relevant place you could possibly be posting this. General Mario Chat...
Yes, that's the code. I think it has to be very exact and very fast, and won't work with the Sonic & Knuckles add-on (there's a much easier code for that.) It has do be after the animation starts, but before the title screen fully appears. Yeah, it's hard to pull off. I think I did it all of twice.
Go Moon!