As I recall that was in the Silver Age when they were giving him powers like nobody's business. This is the "classic" Superman (superstrength, flight, superspeed, superbreath, like 10 types of vision and that's it)
No, I think Clark's just really really good at pin the tail on the donkey. THAT was why he said it would be easy before, not because of his x-ray vision. Honestly, I think that even if Bruce hadn't brought the lead blindfold, he would have kept his eyes shut the whole time. Superman is dorkily awesome like that.