your not the first person whom Ive heard say it came green for certain years of the city. Im just guessing maybe at a time they didnt have type 2 and filled with type 1. Who knows. Even the previous gen city says use type 2 in user manual.
Changing to another one isnt an issue really, but takes a bit more time to ensure old is flushed out. But the difference in cost of buying aftermarket concentrate vs premixed honda isnt that much to begin with.