bkan,
I really don't know if it is officially rated as such for +P ammunition by Taurus (I lost my user manual long ago).
What I can tell you is that your revolver is steel, and in all reality can easily withstand +P pressures. I have the same model Taurus (though blued) and have been pushing +P ammunition through it for ages now with no adverse effects.
If it's not officially +P rated by Taurus, then they may not honor the warranty (if you ever have to use it) if you admit to using non-specified ammunition... but after hundreds of SWCHP+Ps going through my 'lil M85CH, I'd say it's plenty strong enough.