That sure looks like it was leaking before and was repaired with epoxy or some kind of miracle putty . Quite , ummmm , ghetto , as far as repairs go. Billy Mays would be proud.
That would be an ok short term repair , but should have been soldered , or , a better fix would be a new radiator.
What would I do ? replace the radiator , the thermostat , the coolant , any hoses that don't appear to be like new and maybe the belt too. This would be the high road fix .
The low road fix would be more epoxy , some stop leak elixer , pepper or hot dog buns or chewing gum.