This is a really good question, and I think there are benifets to bedding Talley Lightweights instead of lapping them. (Talley advises against lapping)
In practice it is a bit tricky to maintain alignment, but totally worthwhile if your receiver is out of spec.
It's easy to see if this is the case - torque the front base down, but just start the rear receiver screws. Mount the scope and torque the rings. Look at the interface between the rear mount and the receiver. If you can see daylight, bedding might be worth considering.
I am an advocate of positive alignment, and I view lapping rings as a last resort.