if your load temps are 70c then i'd leave it as it is, we can see the card itself is clear for airflow...
60c is well within thermal spec for the card (though a pretty high idle temp), if you reapply the thermal grease you might only gain yourself a few degrees & you run the risk of bricking the card completely by removing the cooler.
if your load temps begin to rise, reapplying paste or aftermarket cooling will be your only option before the card burns itself out.