Tech sites have said that Mozilla probably has their native version already done so it's ready day 1.
But these new rules by apple might put a damper on them actually offering it. Mozilla is a non profit, and apple is going to require a $0.50 tax on every app "for each first annual install per year over a 1 million threshold".
I just don't see how how Mozilla could carry that cost considering they are at over 100 million installs on Android alone.