Changed call letters to which the then-WMAL later adopted. The '7' logo used at the time carried over to the WJLA calls for many years thereafter. (Today they use the same 'circle 7' logo as the likes of WLS, WABC, KABC, KGO, KATV, etc.)
The funny (peculiar) coincidence is, 20th Century-Fox had involvements in both "Lost In Space" and the originally released "Star Wars" movies. As well, Red Skelton's production company, Van Bernard, latched itself onto the TV series. (Wonder if this was on the part of CBS to keep him from bolting to "another network" - as was the case a year later when, to persuade Lucille Ball to sign on for another year of "The Lucy Show," they put then-Desilu production "Mission: Impossible" [another future WFLD staple] on the CBS schedule.) Not to mention that Fox now owns 32, has since 1986 . . .