"legally arrested" lets stop saying arrested, 1000's of people are arrested every day, and the case against them are dismissed and the real criminal found.
Arrest means nothing, if you were found not guity or if the case was dismissed before there was a final verdict.
If you were found guilty and it was dismissed after probation ( first offender program) that is differnet than just being dismissed, the record shows it was dismissed by a first offender program.
And believe me, sealed is only "somewhat" sealed, there are many agencies that can still see those records.