UMLR — Section 11.3.4 isService clarification - Clause 11: Structured Classifiers

Section 11.3.4 says “A Port of an EncapsulatedClassifier is shown as a small square symbol”. Does this perhaps only apply to Ports for which isService is true? The definition of isService would certainly seem to imply that a Port marked with isService = false would not appear on parts, for example. RSA hides the port when you make isService = false.