My DD19 who is 4 1/2 years older than my DS, is not gifted. She has LD's but even without them would not be considered on the gifted end. My DS14 on the other hand could read at 3, and max out his OLSAT when he took it in 3rd grade. There has never been a question he was gifted, and it's quite evident without testing.
In my school district they don't administer the OLSAT till the kids are in 3rd grade and 8 and older. They won't administer tests for LD's until 2nd grade. While I don't completely agree with them there attitude is the tests can be unreliable under a certain age. Children grow and mature quite suddenly, 7 is quite young to "decide" a child isn't gifted like her sister.
I would let your younger daughter grow and learn and not worry about the test results unless you really feel she isn't being challenged or is having problems. Children are different. Testing is imperfect.
