OP, I think perhaps you are in FCPS? I know that there is a process for kids who move in mid year to test in, but my understanding is that they make you wait until January of the following year for acceptance. But if they are allowing you to submit a package right now, that is a good sign.
If it is FCPS, they test all second graders with the CoGAT and NNAT, but there are other forms as well and parents can also submit work samples or outside test results.
We are in FCPS and the GT identification process here is arcane and mysterious! If it is FCPS and you have further questions, I'll to to help if I can.
I would also suggest joining the FCAG Yahoo group (link can be found at fcag.org).