well, i remember belltech offering them in 2 year spans. i think it was the difference between a bolt on caliper bracket and a cast on. there ya go.
http://www.stylintrucks.com/parts.aspx?category|category_root|-30=Suspension&category|cat_-30|373=Lowering+Parts&attribute_value_string|Brand=Belltech&partfamilyid=3350