/me opens up my own tutorial just to find out what that var does....
4050 Unknown or multi-use.
Set to 0x1 after the "Don't go out yet!" OAK Script event.
Set to 0x2 during the Hall of Fame room level script, if the National Dex is NOT already unlocked.
Set to 0x3 after OAK's chat with the player in PALLET TOWN after beating the elite four.
If you removed all of those scripts, then yes, it is safe. That is pretty much how this works. Pick a var, check it, make sure nothing uses it, then go for it.
Well that shows how much I know, thanks for pointing that out to me. :) Back when I started hacking there weren't any tutorials for that so I just had to figure out everything myself. :P just to be sure, from your tutorial, it's safe to just change the number to 4050 for all of my scripts, right?