Not really. They operate somewhat similarly, but a vocoder stretches the formants of whatever the input is across whatever patch you have selected, giving you a wet output of the vocal (or whatever you have for an input) as a complex envelope set to the tone of the dry synth patch.
A talkbox on the otherhand, uses a speaker to emit the sound through a tube in your mouth that you use your lips to form wordlike sounds similar to talking.
Although they both use vocal formants, they will give you different effects. A vocoder will be more chorussy, while a talkbox will be more soloish.
As far as making a vocoder sound like a talk box, I really don't know. It's something I've never tried.