Only risk in trying that is if you overwrote a file you did not have a copy of. If you have copies of all the save files you want to keep then the 30 seconds to restore it if it did not work is about as fun as that gets.
I still struggle to see it working properly if Japanese nicknames are differently encoded to the English ones (at best you get gibberish, at worst you get a crash) and potentially then also different locations for parts of the file (if the game "knows" to read something at one location but because some extra stuff it is not 10 bytes different to where it started you get fun. I would still far sooner pick up one of the many save editors around the place, open one file in one, open the game you want to go to in another and then copy paste all the pokemon, item and whatever data across. I also understand green to be a somewhat more primitive version missing features later seen in red and blue outside Japan so not sure what went for that one.