Yes, Mt. Laurel only has two frequencies for their PD. These are conventional frequencies meaning they are not part of the Burlington TRS. I do believe, though that Mt. Laurel does also have a talkgroup on the trunked system, but I never have heard them use it.
They do have an TG on the system but they don't use it much. I've heard them on it numerous times but they always switch back to their convential channel. I can't recall which site I was monitoring when hearing them, probably the NW region.