They are allowed but be warned that exact replicas are very dangerous, rubber or not.
If you have such a realistic weapon the tip MUST be orange which allows any enforcement officer to judge the situation.
Because the gun is so lifelike, you will have to be careful where you take it and if an officer feels the need, he may show his own fire arm until he feels safe.
I know this sounds silly but it is true and any exact replica weapon can be very dangerous, especially if it does not have safety colors that are easily seen.
Not too many years ago a boy was shot by an officer (at night) while playing laser tag with his friends in his neighborhood because the officer only saw a red dot pointed at his chest.
So again, while rubber weapons are allowed at con, you must be extremely careful in public (for photoshoots and walking around) when they are lifelike. And you must NEVER take them into a mall or any government area...fake, lifelike, or not. It's too dangerous.