Which was the true release date of the original Final Fantasy game?

I personally own a legit copy of the first FF game (the NES one, but in English) and I know thanks to some websites (including Wikipedia) that the game was released on 1987.

Yet on the back of the cartridge, it says '1985', Why? Maybe the cartridges were made years before the release of some games, then the games were saved into the cartridge?

This is the only NES game I have so far, so I can't compare it to other games.


Well I don't know if this is quite the answer you want but the NES was released in 1985.