I'm no expert on libertarianism in political philosophy, but I think I can answer this one: Yes. As I understand it, political libertarianism is a position concerning the legitimate power of the state. One can consistently oppose suicide on moral grounds while maintaining that the state has no business interfering with suicide. One can consistently think that, for various reasons, one morally ought not commit suicide while also thinking that the law should keep out of it. Indeed, a particularly strong distinction between "immoral" and "illegal" seems to lie at the heart of the libertarian outlook.