They are definitely limited. Most of the dealers I have been to says they see one a year. A couple of the dealers said they might get two.
I have read 2400 are made and seeing that there are 1200ish dealers in the USA the numbers make sense.
If you really want a cement one best bet is to get in early - put the $500 or $1000 down and tell your dealer you want one. This way your dealer will get first dibs on a cement and you will see it around January/February.
When you start seeing them hit the lots you can keep an eye out for a dealer that posts one via cars dot com or autotrader and try to get one earlier.
Another thing I was told is that Toyota cannot "order" cars. You can pick your colors/options and they will be first on the list to receive that vehicle or one close to it.