My wife and I were re-watching "Hit And Run" (S01E13), and in it, Kookie gives his address as 18026 Valleyheart Drive. On a whim, I Googled it. It's a valid address, an apartment building at the corner of Sepulveda, right where it crosses the LA River. The apartment house appears to be decades newer than 1958, but it could have been remodeled or rebuilt. I can't help but think that this residence address was a purposeful character detail. Why else use an actual, or at least a possible, address?