In this photo from August 1964, we see that individual Sears and Davison's department stores are in operation. A mall that will connect the two is yet to be built.
Photo from Sears, Roebuck & Company Annual Report 1964

The inline store section of COLUMBIA MALL was over 3 years in the making. The dumbell plan shopping hub, and its initial twenty stores and services, were officially dedicated in November 1967. At this time, the complex encompassed approximately 350,000 leasable square feet, with free parking for 2,000 autos.

COLUMBIA MALL STORES 1967:

SEARS (with Coffee House, Garden Center and freestanding Auto Center) / DAVISON'S (with Coiffures Americana Beauty Salon and Peppermint Snack Bar) / Barricini Candies / Bond Clothes / Castro Convertibles / Davison's Budget Shop / French Cafe / Golden Key Shop / Hahn Shoes / Holiday Shoes / Jarman Shoes / John's Coiffures / Joiner's Barber Shop / Merle Norman Cosmetic Studio / Parklane Hosiery / Pearle Optical / Yankee Trader Gifts / Thom McAn Shoes / Walter R. Thomas Jewelers / Whitney