You have enough bio throughout tank cleaning a rock ain't going to make a difference .
I've never tried the bleaching method, all I would have to say is be careful. Bleach kills the good bacteria that you're trying to grow for your biofilter, so if you do go the bleach route, rinse those rocks like you've never rinsed before.
I believe what Bud29 is saying is to make sure the rocks are free from any residule bleach from treatment..looks to me like you have lava rocks there which are extremely porous,I'd advise against the bleach cleaning for fear of contaminating the tank..just my opinion,better to be safe than sorry...might just give a scrub in water alone&boil for 15-20g mins..I don't give advice&consider it to be the gospel..just my educated opinion&would feel awful making a suggestion to another aquarist that could result in devastation of one's joy& hard work..Just saying
Getcha feet wet fish tank people!