Sometimes. Coatings on drums and platters are subject to flaking off and other deterioration, particularly if they weren't stored in completely perfect conditions. Tiny bits of coating cause head crashes which destroy much bigger parts of the surface. Also, over time, the backer for the rust can deform, which also leads to head crashes. Core memories are fragile in their own way (tiny, brittle wires...), but my gut is they're a bit more resilient that iron oxide coating.