I had to run off to a meeting or I would have posted this earlier. - I really hate it when work gets in the way of my internet time.
I had suspected that it was the stacked humbucker out of the guitar too, but it doenst appear to be - at least based on what I've seen of them.
The reason I say that is I thought that the stacked humbuckers filled the case to the brim, this one appears to only take up about half of the housing. Also it has what appears to be a rectangular magnet across the base of the windings. There is also a solder terminal for 3 wires (2 from the windings and one to ground) that looks similar to what I've seen on the back of the later signature pickups.
I naturally have to run off to another meeting now - stupid work - but will post a few more pictures this afternoon.