Is a person excused for delaying the Fajr prayer past its time if he forgot a prostration and remembered it during the Tashahhud, then repeated the prayer fearing an error, thus exceeding the time of sunrise?

If a worshiper forgets a prostration in the last rak'ah and remembers it while in the tashahhud, he should perform the prostration, then recite the tashahhud, and perform the prostration of forgetfulness (either before or after the taslim). His prayer is valid, and there is no need for him to repeat it. Delaying the prayer due to searching for its ruling or fulfilling a condition, such as ablution, is excused.