Overloading of methods is simply having an object type that has multiple methods with the same name, but different method signatures. Those similarly named methods could be renamed to be different, and have the same implementation, and that wouldn't effect polymorphism at all. I'd say no.
Overriding is when a subclass implements a similary named method with it's own implementation. As a result, objects sharing a common ancestry can exhibity specialized behavior, depending upon how they have overridden inherited methods. Now overriding is all about polymorphism, which is essentially the idea that an object type can take on many different forms at runtime. Polymorphism is all over that.
Overloading - not polymorphic Overriding - the essence of polymorphism