Curt Swan hardly EVER drew covers after Mort Weisinger retired as editor of the Superman titles .... in fact, I can't think offhand of a SINGLE one he drew.
Swan did do quite a few after Weisinger. Just in the Superman title itself, he did 239, 244, 245, 246, 247, 289, 304, and 314 (signed), plus the one you noted. But he certainly was not the regular cover artist.