There is no acknowledgement of any doctrinal similarity and both are largely statments acknowledging Islam's monotheism and that truly devout Muslims who seek God and are ignorant of the Gospel may receive salvation.
There are, I am sure, those who would disagree -- even within the Catholic church's hierarchy, but this in no way embraces the "Mohammedan" religion as Pope Paul VI so interestingly put it. (BTW, notice that he uses "Muslims" in the later document. Guess he got a memo.)
It also differs from Dante's view (medieval Catholic poet) that his hero Virgil is forced to reside in Hell and was not permitted to enter heaven.
And, frankly, it sure beats "death to the infidels".
Think, though. You miss the most basic point here. Did Jesus die for our sins? Islam teaches He did NOT die.
Was Jesus resurrected for our Justification like the Bible teaches? Islam teaches that he didn't even die, let alone raise from the dead.
Is Jesus the Son of God? Islam teaches that God had no Son.
'The basics of Islam teach that Christianity is a lie, so it is immaterial what the sincerity of an islamic believer is, they are condemned to hell without Christ.