I can't answer the first question, but assuming you're referring to Enola Gay bearing the nuclear "Little Boy" payload, the answer to the second part of your question is "probably not."

Nuclear weapons aren't "conventional" explosives: They work by compressing radioactive material, which causes a nuclear reaction. In the case of Little Boy, the reaction was caused by a "gun," which used a small amount of conventional explosive to fire a piece of Uranium 235 onto another piece of Uranium 235, which caused the nuclear explosion.

This is as much a science question as it is a history question, though.