Hello.
There is a strong likelihood that your past record will be discovered by the prosecutor. When the prosecutor runs your rap sheet, they usually also run a check through the National Criminal Information Center database, which provides a criminal history for every state, if there is one. The reason it didn't come up in your past dealings is that generally when you are arrested for a traffic offense, the State usually only gets a copy of your driving record, not your entire rap sheet.
It is possible that because the convictions were so long ago and in another state, and the charge you are pending now is not the most serious, that the prosecutor may make a decision on whether to dismiss your case regardless of your priors.
Hope this helps!
Criminal Justice Lawyer
4 years as a prosecutor, 1 year as a judicial law clerk
Alabama does require registration if you move into the state from another state where you had such a conviction. However, if you were grandfathered out of the registry by the state you moved from, that should be recognized by the new state. To be on the safe side, you should consult with your lawyer as soon as possible so if it does turn out you need to register, you can do it before your court date on the new case.