It's difficult to know about testing accommodations. It's so hard to tell at this early grade since they don't have alot of tests, really, at this point.
We have had in our IEP that our son can have extended time for testing, but he has never used it. We have taken the approach that ideally, we want him to be able to take tests under the usual timed conditions. With practice, he has gotten much faster on timed tests- he aced the OLSAT, SCAT, and our local STAR tests.
The problem, IMHO, with getting testing accommodations into the IEP is that if your child could ultimately get better at timed tests with practice, they will likely not be given that opportunity in school since that would violate the IEP.