Walaikum salaam brother Dawud,
From my humble understanding of the Quran, there is
no exclusivity for anyone over God's favour. God is All-Just.
The greatest favour He completes on mankind is to bring them from darkness into light by sending them guidance, the ability to discern and by bringing them into the folds of true religion. This was the case for the new Muslims in 7th century Arabia as it was previously for the Bani Israel.
There is no dedicated article to your particular question, but the gist of my sentiments can be ascertained from the following article:
WAS THE 'FAVOUR' ONLY COMPLETED FOR MUSLIMS?http://quransmessage.com/articles/was%20the%20favour%20only%20completed%20for%20muslims%20FM3.htmI hope that helps, God willing.
Joseph.