Is the Abrahamic prayer recited in supererogatory prayers?

Praying upon the Prophet (peace and blessings be upon him) is legislated in both obligatory and supererogatory prayers. It is a pillar in both if it is considered a pillar. Saying "Allahumma Salli 'ala Muhammad" (O Allah, send prayers upon Muhammad) is sufficient, and it is recommended to complete the Abrahamic prayer (Salat al-Ibrahimiyyah).