Yes Mark, they will look the same if the destination monitor is calibrated and the application used to view them actually knows what to do with a profile. Firefox and Explorer do not. I have a calibrated mac and softproof in photoshop at this point because I can't (the function does not exist) in Lightroom. I want to eliminate the photoshop step. It's not a matter of what's acceptable, it's a matter of the images looking and measuring the exact same on different browsers on the same machine. Mine.
Thanks for searching for an answer!
Three of the books I've consulted say nothing about how to do this. Presumably you know that the purpose of embedding that profile is to ensure that the colours will be about the same on any display where the images are viewed.