From - http://www.kkklan.com/ -
When Klansmen left the order their records were purged. Also, when the KKK disbanded in 1944, most membership records were discarded. We advise you to contact the county historical society where they lived during the time period of their supposed membership.
From - http://www.adl.org/learn/Ext_US/KKK.asp?xpicked=4&item=18 -
At its peak in 1924, 40,000 uniformed Klansmen paraded through the streets of Washington, D.C., during the Democratic National Convention. Like a modern political lobby, the group was so influential that many politicians felt compelled to court it or even to join, particularly in the Midwestern states. Senators, congressmen, governors, judges at all levels, even future President Harry Truman donned the hood and robe (though Truman shortly quit, apparently disgusted by an anti-Catholic tirade).
From - http://www.crosswalk.com/news/1179625.html -
Gavin told the group that he had never discussed the issue of Byrd's two-year membership in the KKK during the 1940s. The senator resigned in 1943, but is quoted by Scripps-Howard News Service as having written a letter to the imperial wizard of the racist vigilante group in 1946 stating, "The Klan is needed today as never before and I am anxious to see its rebirth here in West Virginia."