Something tells me that a dipole needs two poles.
Not sure how they could guarantee that there would be a ground-plane under it if they were end-fed. Seems like that would be kind of a problem for people that didn't set the device on a couple square-feet of metal.
I just always assumed that the connector on the end fed some transmission-line to the middle of the plastic antenna-assembly, and there was a dipole leg from there to each end. At 12cm = lambda for the 2.4GHz band, the length seems to be about right for that to be the case - yes?
Can't say that I've ever cracked one open to see if that is what's inside though.
73's