One of the 650-1050 nm CFC5A-B fiber collimators (new) from Thorlabs does not have the front yellow covering on it. The one that did not have the covering (left in picture) is labelled #1 on top of the mount.
That is just protective Kapton tape. It will work just fine. It may just be a little more dusty than it should be. You can try the new football-shaped air puffer on it.