I doubt that it is a limited edition. Most of the limited edition frames are at the "S-Works" level. Not "Expert" level.
Here are my two thoughts on it, given that it is labeled as an "Expert" model:
1. It is a Demo bike.
Specialized offers demo bikes for dealers, often times at the Expert level for dealers to loan out for extended test rides. Those bikes often receive special paint jobs, though traditionally, the paint jobs were pretty noticeable, such as neon orange or lime green. They also came with a sticker that said Test Bike, though those could be removed. The bikes are not intended for sale, but the shops do have to buy them and often will sell them at the end of the year.
2. It came from overseas.
Specialized offers different paint jobs in different countries. My wife, for example, as an Amira Pro that has a paint job that is only offered in Belgium as far as we can tell. (She got it directly from Specialized and you can find her listed under Specialized's Riders on its website.) You will have to flip through a bunch of different country sites to find it, which means a lot of clearing your browser history to go to a different Specialized country sites.
And, as said, it could be a fake.
I am riding an 2009 Tarmac Expert, test bike. When I google'd it, I am easily having some information about my frame. It was a white one with purple details.
This frame, I couldn't find it anywhere on internet. And seller also said it is not test bike.
And more, the seller says that he has serial numbers on the frame and it registered to his name. So my friend asked direct information from Specialized that, this serial number registered to that name and frame is under specialized's warranty.
Thanks for other informations also