I have no idea of when, but it appears as if HL has at least done the prototype work on a M3 tank.. The question I would have is this a 3 D printed prototype done to discover the molding requirements for mass production, or do they now have this one waiting in the pipeline ready to release and is in the production plan. The picture of the M3 is part of the changing banner with zero details. It is just a picture.

http://www.hayaltd.co.uk/