They aren't the same for object references. The reference can't be changed, but the properties can.
Depends on the language. In C++
const std::vector<int>& foo = bar.GetVector();
std::vector<int>& foo = bar.GetVector();
Depends on the language. In C++
foo is a constant object reference cannot have its properties changed (and also cannot be changed to refer to a new object). Is an object reference that can have its properties changed (but cannot be changed to refer to a new object).