PhilmoYou'll need to "request" this drop after it has ended. A minimum of 200 Requests are required for this drop to happen again. This is the standard for all Massdrop "drops".
PhilmoYes, this may drop again in the future. However, it's really hard to say when it will drop because we are selling through much of Orient's inventory. It may take some time for them to restock. That said, if you are really set on getting the grey, I'm sure you can find it available through other sales channels, albeit at a higher price.