Does the plan require actions, or is it for reference only?
I think the fundamental concept of GTD is that every piece of information in your life is either actionable, for reference, or for the bin.
Perhaps you can extract all the actions that need to be taken, and projects that need to be completed, from the plan, then file the plan away for reference.
Or, maybe the plan contains guidelines. These guidelines would be reference material to refer to when doing a specific task or project.
Or maybe the plan is a piece of junk. Then file it in the round filing cabinet (aka waste-basket).