How to get a noise/grain sample and apply it later?

I was wondering if it's possible to get a noise or grain sample from a specific video camera and then apply it later. I'm rendering some stuff in Modo that then I have to bring into AE for compositing, and I want to match the rendered model to the footage as close as possible, and one of the things I need to do is match the grain. So far I did it with the grain filter, and it's not bad, but somebody at the Luxology Modo forum adviced me to get a noise sample and then apply it to the composite. Is this possible in AE, and how?

Thanks,

Sebastian