The reason shows got green-lighted with very few stations back then was that barter was the exception, rather than the rule as it is today. Stations paid cash for them and kept all commercial inventory. As Trainman pointed out, KABC had it, as well as WABC and WXYZ Detroit (at that time an ABC O&O.) If WLS and KGO were on board as well, that would be enough to start production. Some of the other games that had low clearances in prime access were DC with 47 stations, WML with 46, Concentration and J! with 37 and Masq. Party with 20 stations. Most cleared were LMAD with 129 markets, TPIR with 124 and HS with 122.
Nowadays, of course, national advertisers have to be on board before a show is declared a firm go, and the show must have commitments from virtually every market in order for the national advertiser to be interested.
In that same issue there was an interesting article about a gentleman named Eugene Jones, who specialized in making documentary films that take years to produce, edit and finish. From the article. "So what does he (Jones) live on in the meantime?.......the riches from "Sale of the Century," a game show he syndicates in 48 markets..."