While it obviously depends on when Sonos is getting the next shipment of white Roams, it also will depend on when you preorder (first ordered/first shipped), how many others preordered ahead of you, and how many units Sonos is getting in the next shipment.  Don’t think anyone on the forums, including Sonos support personnel, has access to the data to give you an answer.  You might try contact Sonos sales.

Danny’s correct, you need to contact Sonos Sales to get an update on your order as we can't provide that support here.