I'd say if it was completely missing, there shouldnt be a concern.

However if it appeared to be installed but not working, it really should fail.

Just because it didnt lock up at the test, doesnt mean it would be 100% safe. But that online manual definitely states it should be present and working, and most stuff in that manual are old, not new, amended 1.5 years ago )
But as with all items, it will be down to each individual tester.