Our school volunteered it (iq and achievement testing) when I told them about my DS and that I was interested in skipping or doing subject acceleration. I would just suggest to tell them what your concerns are, some possible solutions you've come up with and then ask for their help and advice. I'm not sure they are required to supply it or not, and maybe they have different requirements for different states. But I think they are very interested and probably required to do testing before supplying differentiation of extreme measures.
