Yes, don't do it if you want to maintain the value of your cue. This is only a good test if you have a place to hide it, like under a bumper or something. If it is a plastic, the pin will go in and you can't hide it.
Take your cue to a cue repair guy or a cue builder. They should be able to tell you one way or the other. I think there is also a black light test you can try. Ivory will glow under a black light. I am not so sure about how accurate the test is though.