There's nothing I see to get the Data Source selected for the xpTextObject, but on a Take Item in sequence, you can retrieve the PropertySourceType for a published object to see if Static, Datalinq or Widget is selected with a script like this:
dim takeitem as xpTakeItem
dim text1 as xpPublishedObject
dim type as propertysourcetype
engine.Sequencer.GetFocusedTakeItem(takeitem)
takeitem.GetPublishedObjectByName("Text1",text1)
text1.GetPropertySourceType(0,type)
You can check to see if the type is 0, 1 or 2 to determine which Data Source type is selected:

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Jeff Mayer
Ross Video
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