Yes. Dd just used the one from the SSAT people, and she also credited ALEKS math (online tutorial) for a good specific prep for SSAT. Ds just took the actual test in 6th and 7th for practice and evaluation at his small private school, then for high school admissions purposes in 8th.
SSAT tests by grade level, yes. You are scored with the cohort of the grade that you report your child to belong to. (Test as a 6th grader, get compared to other 6th graders.)