It's highly unlikely they would remain that close unless they split apart very soon before impact. Solar radiation exerts a small force on any object in space that depends on the object's orientation, reflectivity, rotation, etc. This introduces a small variation in it's flight path that can add up to several kilometres of uncertainty in just a few weeks. So even objects with very close flight paths, but differences in structure and rotation, will diverge. Objects with low mass to surface area and an elongated shape, such as empty fuel tanks, are subject to particularly high uncertainty in their trajectory.
