AT&T's version of the Galaxy J7 2017 seems to have passed through the FCC recently which could mean that it's getting closer to a launch on the U.S.' second largest wireless carrier. In the FCC filings and documents you can see the model numbers SM-J727A and SM-J727AZ. While it's quite likely that the SM-J727A model is the model number for AT&T, the SM-J727AZ could be a model meant for Cricket Wireless or it could be for another carrier or region entirely.
The Galaxy J7 2017 version initially showed up at the FCC back in February with the model number SM-J727P and then was later rumored to be coming to AT&T's network, but it's also been rumored to be coming to Verizon's network, as well as US Cellular, Sprint, Virgin Mobile, Boost Mobile, and Tracfone, so most consumers regardless of carrier seem to have a variant on the way. There isn't really much detail in the FCC documents about this model of the phone, but a device believed to be the 2017 model of the Galaxy J7 showed up on GFXBench back in the beginning of February with Android 7.0 Nougat as the software version, alongside a handful of other listed specifications and chances are that they will be mostly the same specs across the variations of the device, save for any models which are outside the U.S. which could have different processors.
According to the GFXBench listing the Galaxy J7 2017 could have a 5.5-inch HD screen as well as the Samsung Exynos 7870 octa-core CPU, though the U.S. models like the one heading to AT&T could very well come with a chipset manufactured by Qualcomm instead as this wouldn't be the first time that Samsung opted for a Qualcomm chip in U.S. variants of its devices, while using its own in-house Exynos chips in other international regions. The phone will also likely come with 16GB of internal storage as well as 2GB of RAM according to the benchmark results, and it's also likely to have a 5-megapixel front camera and an 8-megapixel rear camera. With that in mind, none of the specs and hardware are official until the device has officially been announced.