Gateway International Raceway's Public and Media Relations Manager Brandon Mudd sent this along, from a show transcript at the Howard Stern website:
The true origins of the Roll Call piquing the insatiable curiosity of Howard 100 News. Nick Vidal, one half of Los Angeles’ Baka Boys tells reporter Steve Langford that the corporate bosses at Emmis Communications took their World Famous Roll Call and gave it to the guys at sister station Hot 97 in New York. Vidal declaring their Roll Call was a lot better than the one Ed Lover, Dr. Dre and Lisa G did in New York. But Vidal acknowledges they came up with the Roll Call in LA after hearing about a St. Louis DJ who did a Roll Call segment every morning back in the 1970’s. DJ Rod King credited with doing just that at St Louis station WESL.
Thanks, Brandon. Sorry I called you Eraserhead.