I would go more than two weeks, but that's just me. It is not just to cure it, like normal, to eliminate die-off. It is to get out detritus, sand, gunk, etc from the cavities in the rock. You want to get it all out because you do not have any substrate to absorb it or collect it. It will sit on the bottom or blow around because you will (typically) have higher flow.
You want to do more than just let the rock sit in a can for two weeks. I would use two trash cans Put the rock in one and let it go a few days with some good circulation. Then, I would use another can to swish, rinse, blast with a strong powerhead, and otherwise force the loose stuff out. Then back into fresh/new water. Repeat about 4-5 times or until no more detritus etc can come out. You want the rinse water to be clean.
I know if sounds a pain and a lot of work, but a lot of work now will help keep that stuff out of the tank, which is the primary reason to run BB in the first place.