No. Berg is not John Doe #2.
Berg was in Oklahoma City at the same time as the 20th 9/11 hijacker Massoui (spelling?). Somehow Massoui ended up with Berg's password and e-mail information and the FBI interviewed Berg about that matter following 9/11.
It is an interesting coincidence that a man beheaded by Al Qaeda had his e-mail password compromised (at least) in Oklahoma by an Al Qaeda member.
The reason Oklahoma came up further in the conversation is because it is a central meeting point for terrorists.
Three of the 9/11 terrorists stayed at the same hotel as John Doe #2 in the OKC bombing. At least 24 people saw John Doe #2 (who is identified in the book The Third TErrorist) with McVeigh before the bombing. The country's largest contingent of ex-Iraqi Republican Guard expatriots lives in Oklahoma City.
SO WAS THE REST OF OKLAHOMA CITY