What if my pre amp (or TT or phono pre) has no ground pin on the power cord, just the power amp?
Consider yourself lucky. Provided of course that the chassis meet Class II specs and don't actually require the safety ground. The safety ground is the biggest source of ground loop and other noise.
What orientation now for the shielded IC's?
Same as you would otherwise.
The safety ground isn't a ground in the traditional sense. It's just connected to neutral back and the service panel and serves as a path for fault currents should there be a failure in the AC mains in the equipment which might otherwise cause the chassis to go hot and create a shock hazard.
It doesn't serve any purpose with regard to component grounding.