The seal does not look bad and does not seem to show signs of leakage; but, they are relatively cheap from RockAuto so I would be inclined to replace it while I had access unless it was relatively new.

Over filling the crankcase will lead to increased leakage from the back of the rather useless oil pan gasket.

Something else to check. Look at the front seal on the transmission. I had my gearbox out of the car while I was doing resto on the body. Figured I should replace the gaskets and the seals on the box. Did the front seal even though it showed no signs of leakage. Now it leaks! I know this because I use Red Line MTL and the slow drips coming from the bell housing area are the nice red MTL.