The FCC certification is necessary for products that plan to be launched/sold in the US, so seeing these devices does hint that it could be close to launch. CES 2019 is kicking off in the middle of next week which means that there is a good chance that these speakers could be shown off then.
The speakers in question appear to be a satellite speaker that will help enhance the Sonos Playbar and bring about surround sound. Given that soundbars are generally one direction where it is pointed directly at the listener, it does seem a bit limiting if you’re hoping to achieve a surround sound experience, which is where these satellite speakers come in.
It is unclear if these speakers will be able to function by themselves without the need for the Playbar, or if they are dependent on the Playbar to create a surround sound experience. However like we said, CES is next week and usually quite a few audio products are announced then, so hopefully we’ll have more details then.