I recently owned both the Am Standard and Am Special Jazz basses. I traded the Standard in for the Special. As stated, the Special has the slim C profile neck. Also, the Special has the pups Fender used before switching to CS in the Standard. Lastly, the Special has the ' Greasebuckut ' tone circuitry.
There could be some truth as stated above that the new sandblasted limited edition are replacing the Special, at least for now. I was looking at Sweetwater and they had 4 of the blue sandblasted ones. One(1) had a pickguard sticker just like the one on my new Special, mentioning the slim C and Greasebucket circuitry. I emailed a salesperson to see if this was the case, iow, if they all had the 3 features, neck, pups, circuitry. He said he'd check into it but i never heard back ... still curious.