Destiny Question

So i recently acquired a legendary sparrow and i love it. I want to buy the Emerald coil for it but i do not know if it will work. I have looked around and nothing says anything about it. Please post if i can or not and please site the source i really dont want to waste 23 strange coins.

40 seconds, it says Rare Sparrow with a box ticked, I assume it only upgrades rare sparrows.

Just buy it. If it doesn’t work, then oh well.

The upgrade is only for turning a rare sparrow into a legendary.

Don’t buy it, only works with rares for some dumb reason.

Or you could buy it because the emerald one looks badass anyways, then upgrade a rare vanguard sparrow for a second character