Immigration attorney asked us to send our fingerprints off to California SBI?

I hope you can answer this. My friend is filing for his residency. He sent in his FBI fingerprints just to get a clear criminal record. He was 16 years when he was found guilty for being an accomplice to a drive-by shooting. However, this happened 30 years ago. The San Bernardino Courts sent him his record stating that due to the age of the case, the file has been destroyed and is no longer in their records. My friend is applying to get his Permanent Residency under the 245-i law. However, his immigration attorney told him that he should submit his fingerprints to the California S.B.I. Can someone tell us what all this involves and if this is really necessary after submitting the fingerprints to the F.B.I? Personally, I think it's an unnecessary step. But what do you think???