Certainly looks that way, with job listings on Square Enix's European website asking for a whole bunch of new game "masters", all of them due to start work in just over two month's time.
The vacancy listings are asking for people familiar with MMOs and Final Fantasy XI in particular. The fact there are so many of them, and they're all due to start work in "mid-September" points to a public beta (they've got to be overseeing something) for Final Fantasy XIV if not in that month, then shortly afterwards.
After all, the chances of Square hiring a ton of people, all due to start in the same month, to oversee Final Fantasy XI are... slim.
Rumor: FFXIV beta may begin by September [Massively]