Possible but it seems unlikely
I believe they suggested the water was there for a very long time because it had acted on the rocks. It doesn't seem likely a small impact would create a body of water that would last long enough to create the results we see in these rocks. (Then again I'm a complete amatuer in this field so what do I know?) When they get to the big crater named Endurance about 700m to the east they will have a better idea if the rocks were actually layed down by water.