@alexcurylo has confirmed that barTintColor can be installed in IB. Part of the problem was that I could not figure out how to select the NavigationBar (I am not a normal user of Interface Builder) ...
Just in case, this helps someone else, I was able to select the Navigation Bar as a child of the Navigation Controller using the Document Outline panel (I could not do this by clicking the left / right visual presentation ...):

After the selection, as @alexcurylo pointed out, it was just a setup in the Attributes Inspector .
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