This topic has been debated a few times, but yes, if your read noise is always lower than shot noise then ISO could become metadata. You'll have to leave ISO at base ISO, not auto, otherwise you'll gain nothing.
As I see, current Raw converters don't handle this yet. I think it is an easy function to implement, so that the raw data is multiplied by a factor before any processing.
There are cameras like the digital cinema Red cameras, several MFDB that handle ISO as metadata. Also the new Fuji X100 does this at ISO above 1600