create array from object values in order

I found a similar function from lodash but the documentation says:

_.values({ 'one': 1, 'two': 2, 'three': 3 });
// → [1, 2, 3] (property order is not guaranteed across environments)

For my use, it is important that the order is preserved, my object will come from a result of mongoose.

I checked the source code:

function values(object) {
      var index = -1,
          props = keys(object),
          length = props.length,
          result = Array(length);

      while (++index < length) {
        result[index] = object[props[index]];
      }
      return result;
    }

It seems to me that it does keep the order, but why the warning on their documentation?

If objects don't have order then how would this work?

(function() { return _.toArray(arguments).slice(1); })(1, 2, 3, 4);
// → [2, 3, 4]

Isn't the order of the arguments important?