The Lexus parts book shows offset front bushings for the lower control arm. Is this the factory way of adjusting for camber?

 

No this is just a lower rear control arm bushing and has no adjustment for chamber.

Adjusting the chamber should be on the top a-arm/control arm on the body #10 on the diagram the 2 bushing on the end there should be dials on the bolts that push against the body thats where the adjustment be for chamber.