I was active duty U.S.Army from 1973 to 2001. I signed up for Social Security Retirement (January 2017. How can I tell if I'm received the special extra earnings for periods of active duty to be credited to my Social Security earnings record?
Starting with 1968, Social Security began automatically adding deemed military wages for periods of active duty. About the only way to see if you received the extra credits is to compare the amounts posted to your Social Security earnings record with the amounts shown on your W-2 forms from the military.
That said, in my 36 years with Social Security, I don't recall ever encountering a case in which the appropriate credits weren't added, so I believe you can rest assured that the appropriate military credits were used in calculating your benefit rate.