Is it obligatory to re-pray the Fajr prayer as a make-up (qada') after performing it on time (hadirah) when in doubt about the entry of sunrise, with darkness still present on the horizon?

Whoever is obligated to perform the prayer at its prescribed time, then if he prays Fajr while darkness still prevails, his prayer is valid. He is not required to make up (qada') the prayer even if it later becomes clear to him that the sun had risen. And if he prays while he thinks the sun has risen, but then it becomes clear that it has not risen, his prayer is valid. The intention of performing (ada') a prayer substitutes for the intention of making up (qada') a prayer, and vice-versa, according to some scholars, and this applies to unintentional cases. However, for one who intentionally delays the prayer, his prayer is not valid.