Negative and correct. They're not only redundant, but would cause trouble in short order.
The new bearings on the Extreme axles are what's known in the industry as the "Set-20" that you probably have heard of. They're exposed tapered roller bearings that rely on gear lube from the differential to keep them lubricated and happy.
Installing the original seals used with the original sealed ball bearings would starve them of lubrication.
The rubber lip around the outside of the new bearing's outer race is the seal. They are also sealed in their inner race area so that the lubricant does not leak out past the axle shafts.
So what you are looking at is a bearing and an inner race that's pressed to the axle (just like original) and an outer race with seal that is shipped in an assembled position. It's pretty well stuck in there as well, until it's installed on the axle housing.
Once installed and driven for awhile, the next time you remove the axles the seal and race may very well remain in the housing, and what you'll see on the axle shaft are the exposed (but still captured) tapered roller setup.
The original ball bearing design wasn't all that well sealed as all it had to do was hold in it's grease. So the inner seals were needed to keep the oil away from the bearing.
This is not anything aftermarket-exotic. It's what Ford did on their heavier duty 9" rear ends anyway. The axle shafts are slightly different size, so the two bearings are not interchangeable, but they fit the same large-bearing housing ends.
The new bearings are thicker however and will stick out about 1/4 or so proud of the housing end. So when they don't look like they're all the way seated, don't panic!
The ball bearings had a life expectancy of about 100k miles. The Set-20 tapered bearings could conceivably live as long as the vehicle if they're not abused, but because the seals will eventually leak, that's the time to replace the bearing too, since they're not sold separately.
Too bad, but it's also probably a smart thing to do. Still probably end up renewing the bearings every 100k miles or so.
Paul