A listing for the Galaxy Tab S3 has confirmed the tablet went through the FCC and could be announced shortly. Though not confirmed, it's possible we will see the product during MWC. The device has the model number SM-T825, according to the FCC listing.
Not much information was provided by the listing, although it did include a sketch of the device's rear.
If Samsung takes the same route as it did with the Galaxy Tab S3's predecessor, there will be two versions introduced, an 8-inch and a 9.7-inch variant.