I doubt they destroyed anything because of a lawsuit, particularly as that's specifically illegal, but there was a major fire somewhere way back that destroyed a large part of the existing production info, which wasn't very good anyway, the common breakdown was just "light truck/heavy truck", and even that was calender year production and registrations, not model year and nothing about options, which is what the Cameo really is, they didn't really start keeping good track of specific numbers until the 70's
Bill