Is it permissible to call the monotheist Christians before the Prophetic mission "Muslims"?

The Christians who believed in the Oneness of God before the advent of Prophet Muhammad, peace be upon him, and who believed in Jesus, peace be upon him, and what he brought, are considered Muslims. Allah Almighty affirmed their previous submission (Islam) in the Holy Quran and promised them a reward, citing the verse: "And when it is recited to them, they say, 'We have believed in it; indeed, it is the truth from our Lord. Indeed, we were Muslims [submitting to Allah] before it.'" (Al-Qasas: 53). Ibn Kathir, Ibn Atiyyah, and Al-Tabari interpreted this verse to mean that they were monotheists and devoted to God, following the religion of Jesus, peace be upon him, for the religion of Jesus is Islam.