Do You Have: Remington 550 "O K", "W K", "D K" , or "E K" ?

[usabaker]

Greetings folks! I'm in the process of writing a book on the Remington 550 and need some infromation. For those of you who have a Remington 550 with the following date codes:

• "O K" July 1941
  "W K" August 1941
  "D K" September 1941, or
  "E K" October 1941

Can you tell me if you have the defector threaded screw hole on the front top left of the receiver?

Thank you in advance
Bill