This means that Microsoft has submitted the two models for testing of their wireless equipment, which incidentally is the same for both models.
Another interesting snippet of information if that model 1682 apparently includes the same user manual than the model we have now in our homes, but 1683 appears to use a different one.
Unfortunately, nothing else is known, because the documentation that includes the actually juicy bits is inaccessible until June 25th for model 1683 and July 29th for model 1682.
It’s worth mentioning that this doesn’t mean that we’re necessarily looking at “slim” models or big revisions, as this kind of filing could very well belong to small revisions like the CUH-1100 and CUH-1200 PS4 models released in the past two years.
It’s also not safe to assume that the filings indicate two different iteration of the console, as one could be a dedicated DevKit. We’ll probably know more in the coming months.