Well the normal workflow for grading is that the AAF or XML from the offline edit goes to the Grading system and the Grader connects to the original sources linking them to the ingested composition.
So at that stage you have all the original sources available in all their various colour spaces and LUTs etc.
If you link in Avid you have the choice of leaving the footage as it is and transcoding or applying a corrective LUT and transcoding (but not embedding that LUT, it still lives sitting on top of the media) or Transcoding and embedding the LUT (so you can no longer get back to the original look without reverting to a pre transcoded version)
So it depends on what you workflow is to be.
Pat Horridge
Broadcast & Post Consultant, Trainer, Avid Certified Instructor
Free online Tutorials at VET digital media academy online https://vimeo.com/channels/752951
pat@vet.co.uk