That would seem correct. In the Catholic traditional Latin Mass the reading from the epistles is called 'Lectio'. For example, this Sunday's is introduced with "Lectio Epistolæ beati Pauli Apostoli ad Ephesios", or "A reading of the Epistle of blessed Paul the Apostle to the Ephesians."
"Discipulae" is the feminine plural nominative of discipulus,a, while "discipuli" is the masculine plural nominative.
"Discipulos" is the masculine plural accusative. The accusative case is used with direct objects, or with indirect objects if paired with certain prepositions (e.g., ad for motion towards a place). This sentence uses discipulus,a as a subject; therefore it requires the nominative case.