Yeah after 1000 years you'd have a very toxic paperweight and not much else. One thing that is often overlooked/misunderstood about nuclear bombs (Hollywood deserves a lot of blame for this) is that nukes are detonated by a controlled explosion directed at the nuclear matter, any defect within this triggering mechanism and all you get is a small (relatively anyway) explosion and a scattering of the nuclear matter, a far cry from the blast of a controlled nuclear detonation.