1971 Duster Rallye Dash - Unidentified bezel

Between the light switch and the speedometer, there is a 5/8" diameter round chrome bezel, with a very thin threaded rod protruding out of it about a half inch. As far as I can tell, the rod does not turn left or right, but does pull out/push in about 1/8". I didn't see any reference to this in the owner's manual booklet or in the electrical section of the chassis service manual. My guess is that it is a trip odometer reset? Is there supposed to be a knob there and what does does the knob look like?

Thanks from a FABO newbie.

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