: Double-post top latch design for improved locking.
The original Iver Johnson company went out of business in 1993. While they kept internal production records for many years, this data is not publicly accessible online. The vast amount of information available today comes from the painstaking work of dedicated researchers and historians, most notably the late W.E. "Bill" Goforth. His life's work is widely regarded as the ultimate authority and the best "database" available. Iver Johnson Revolver Serial Number Database BEST