The beauty of the hobby is that there are no rules regarding first appearances. "First appearance" is a term of art not a dogmatic dictate. In this hobby, the phrase has two meanings, the first being the literal first appearance, the second being a less literal translation and would be more literally interpreted as most valued early appearance. The second definition is what most hobbyists refer to when they say "first appearance". While this may not always be literally true, most comic collectors appreciate the nuance. See AMS 300, Hulk 181, TMNT 1 ... ad infinitum.
Perfect explanation.
Not for Mr. Ween.