I think its males on the left, females on the right but I'm not sure. Guess it really doesn't matter. You can just make up your own system.
I don't like those plastic colored spiral bands except for temporally ID'ing because they always seem to fall off. I've resorted to using zip ties for temporary ID'ing but one has to be very careful with these so they don't tighten themselves. Snip off the extra end so the goose doesn't play with it and accidentally tighten it.
Or you forget about them and they cut into the leg of growing birds.
I've also got those soft aluminum bands you need a special tool to put them on.
They work fine but seem to bend alot while putting them on and don't look very good.
I like the solid more heavy duty metal bands you just slip over the ankle and pinch together to close.