Call the map unit abbreviation in dynamic text

[JJ_Reyes]

I am using <dyn type="mapFrame" name="Map Frame" property="mapUnits" /> to add the map units on my layout.

Is there a way to call up the abbreviation? I have tried variations of <dyn type="mapFrame" name="Map Frame" property="mapUnits" abbr="true" />, but that is not working