Lumen Gentium Chapt II 16:
Finally, those who have not yet received the Gospel are related to the People of God in various ways.[18] There is, first, that people to which the covenants and promises were made, and from which Christ was born according to the flesh (cf. Rom. 9 :4-5): in view of the divine choice, they are a people most dear for the sake of the fathers, for the gifts of God are without repentance (cf. Rom. 11:29-29). But the plan of salvation also includes those who acknowledge the Creator, in the first place amongst whom are the Moslems: these profess to hold the faith of Abraham, and together with us they adore the one, merciful God, mankind's judge on the last day.
Let me repeat: "...and together with us they adore the one, merciful God..." This statement is incorrect. They do not adore the merciful God Of Abraham. They worship Allah, the hater of all Gods people. The one that commands the murderof all Christians and Jews. This is clearly not the God of Abraham.
Clearly the ignorance of Islam is not covered by Rom. chapter 1, which clearly states that for worshipping the wrong God, there is no excuse.