The original arrangement of the two original parts at the end of the torque tube are/were as you describe:
- an interior seal
- an exterior bushing/bearing
The replacement that you have is/was called an "Okie Bushing" (because of where it was made, and, perhaps because it a allowed a quick&dirty repair by almost anyone with a few tools). This type of replacement serves as both a bearing/bushing and a a seal.
This arrangement/repair-part allowed a "quick & dirty" repair of the bushing/bearing&seal:
- it allows for pushing back ("out of the way") the old bushing&seal (easier than removal; and, "out of sight - out of mind")
- it provides the new bushing/bearing & seal
- it saves a lot of time and effort
When doing a R&P replacement, this type of bushing is not really needed (you could easily use a separate bearing/bushing and seal), but, the Okie style bushing is readily available, at it works well.
