Dear Dbartlett,
There is no direct access to this information, neither inside and certainly not outside of Revit.
Here is a risky, unsupported and untested idea for a possible workaround:
You could try opening the project, subscribing to the DocumentSynchronizingWithCentral event, attempting to save to central, and then cancelling the event if it is raised. It may be that the event is not raised if the project has already been fully synched.
The documentation says that this event is cancellable:
This event is raised when Revit is just about to synchronize a document with central model.
Handlers of this event are permitted to make modifications to any document (including the active document), except for documents that are currently in read-only mode.
Event is cancellable. To cancel it, call the 'Cancel()' method in event’s argument to True. Your application is responsible for providing feedback to the user about the reason for the cancellation.
However, our experts do not recommend cancelling it without a good reason, so it is up to you whether you really want to try this out.
Good luck and best regards,
Jeremy
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Jeremy Tammik
Autodesk Developer Network -- http://www.autodesk.com/joinadn
The Building Coder -- http://thebuildingcoder.typepad.com