Can fcp 5.4 use HD 1920 x 1080 footage in its proper aspect ratio?

I just got a Cannon Mark II 5D and am using fcp 5.4 to edit video.

I am not using capture and log... just dragging it in to the project bin. None of my project settings are 1920 x 1080. How do I set my aspect ratio properly?

And... to throw a kink in the mix. I did not realize this right away. I've been editing for a while. But, I'm set at a different aspect ratio. Can I change this midstream?

Thanks for you help.