ICS won't be "released" on Tuesday, it will be announced. The Nexus Prime (or whatever it's called) will ship with it, because that's what the Nexus does--showcase the latest and greatest Android code.
Once the ICS is actually in the hands of manufacturers, then they'll have to test it and optimize it and etc. Even if they already received the code, I imagine it'll be some months before we'll see it. Motorola being in the process of getting acquired by Google might help us somewhat, but I imagine the New Year will come and go before we see ICS on our Photons.