I was looking at the Rigger 3 book, I skipped 4th ed. Anyway, the long-haul truck in that had 0 armor, and by that scale it has the same armor rating as a sedan. Not that armor ratings in 3rd and 5th really compare. Also, both the GMC Bulldog and Ares Roadmaster are armored vehicles by default. The Gopher has a 10 armor though, which might be more appropriate.