wheel hub and bearing needed replacement. 76,000 mileage.
Is this unusual? on 2006 Buick Rainier

Since car seems like extra good features, should GMreplace this sealed unit?

Asked by for the 2006 Buick Rainier
no, common fialure. if you are going to do 1 i would do both of them.
the brake dust gets into the bearing causing the failures.