AT&T's (apparent) use of plug-in Gen II

This doesn't come in the form of a news article, but rather by a picture below which was news to me. Photo was taken with a cell phone cam in a strip-mall parking lot in metro Detroit.

AT&T in S.E. Michigan has apparently been using plug-in Gen II Prius's as company vehicles. (I could be misinterpreting the picture, but it looks like a plug-in port right next to the gas filler.)

Is this practice common elsewhere? I didn't know they were in commercial fleet use.