I doubt your record was "automatically sealed". If it was sealed, great, because you can now expunge the record. Expunging a record is better than a seal, as a seal can remain visible to the public even though the physical court file has a piece of tape around it noting "Sealed-Do Not Break Seal Without Court Order". An expunge would erase your records from FDLE, and that's what you want.
The clerk is the only entity that can give you a certified copy of the disposition, and on a case that old, they may not have an "actual" copy, they'll probably print a page off their computer and certify that (I've had it done, it works...). The clerk should be able to tell you whether or not the file was "sealed", but because sealing a file involves a bit of process, you would have probably known about it had this actually been done.
If adjudication was withheld, you never lost your civil rights. You may still vote, carry a firearm with a proper permit, etc etc.
While it's likely that your record wasn't sealed if it's showing on an FDLE public record (it would still be available to law enforcement even if sealed) - you should be able to have an attorney seal it for you. This is not unusual on a very old case. If you received a "withheld adjudication" you have not lost any civil rights unless you plead "guilty" vs. "no contest". If you plead "guilty" and had a withheld adjudication -- federal law currently considers it a "conviction" although Florida law does not.
My colleagues are correct. Your record was probably not sealed. Now, on a leaving the scene of the accident -- depending upon how that was charged 30 years ago -- a withholding of adjudication provides the protection to prevent loss of civil rights, including those mentioned in your comment.
Please understand that an expungement/expunction of a record cannot normally occur until at least 10 years has passed since completion of your sentence. In your case, this will likely not prove a problem.
Mr. Guidry is correct on the important distinction between having a criminal record expunged, and simply having one sealed. Unfortunately, sealing is a mechanism that can be invoked immediately following completion of a sentence on a qualified offense in which a withholding of adjudication is attached. Expungement takes a longer wait.
The Brett Law Firm, P.A.