Yes, according to the current portable perks booklet, there is a 10% DVC discount at both The Mara and Boma. There is also a 10% DVC discount at Jiko, but is only for the hours of 5:30-6:30 pm and 9:00-9:30 pm.
There wasn't one when I went this September. I was told at the time that the perk would start with the new year. From what I've just read, it would appear that they started it early.