The current raw scores likely can be re-converted to T/standard scores using the correct norms. The situation in which they might be overestimates is if the student has errors soon after the start point that suggest that they might have had a lower basal, with additional errors, if they had been started earlier overall, at their true age-based start point. Though I see now that you gave the approximate ages--I don't recall off hand for the RIAS-2, but typically those ages have the same start points on the majority of tests of this kind. So that probably won't be an issue.
You definitely cannot repeat the test, unless it has been 24 months since the previous administration. That would invalidate the second result.
Just have the raw scores re-converted to standard scores, using the correct age norms. I am assuming this is a child of at least average ability, so the basal issue that might or might not occur is very unlikely to affect results.
