I agree with MoN. Gifted is still gifted. What does the law say? They can't ignore the law.
I would push to keep the plan in place, even if it says, "He will follow the second grade curriculum." It's possible that he'll need more acceleration at some point, and it's easier to modify an existing GIEP document than to start a new one.
Sometimes schools don't understand giftedness, and they may genuinely believe that a grade skip is enough. It may not be.
Don't let them push you around if you have the law on your side. Be gentle, but firm.
