Seiko Lord Marvel, manufactured in May 1958 Model number 14057 Movement with the serial number on the mainspring receiver, the earliest type Dial: Wedge-shaped index, solid gold Redone Faithfully reproduced Crown: Newly replaced Windshield: Newly replaced Belt: Cordovan (made-to-order) Seiko antique buckle Seiko antique box It seems that the SD mark was not added until May 1958. I have confirmed that the SD mark was added from the June production. If you search, it seems that the first shipment was in May. The dial without the SD mark was only for one month.