If you are referring to if there is a Google Play App available on the NowTV boxes or smart stick, then no this App is not available via NowTV branded devices sorry.
Should you be looking for a device with the Google Play App, then perhaps consider the Roku Express which has Google Play for TV & Movies, NowTV, Netflix, Amazon Video, BBC iPlayer, ITV Hub, All 4, Demand 5 and numerous other Apps on the Roku channel store.
This is so unfair. Many of us would welcome the Amazon and Gogole apps to play our content on Now TV, without yet having to purchase yet another (Roku) device. Thisis further complicated by only being allowed 4 devices and this counts Chromecasts which cannot be used in isolation without a phone or tablet. I could buy more boxes to get more vouchers, but then I would need to set up multiple accounts. I see there is a 4K version of the Roku box? I also hear talk of an Apple beta app? Perhaps if the Roku price drops in the New Year, I may add it?