Phil -
Demaret also won the Matchplay in 1940 when it was played at Lake Merced.
From 1930 to 1946, the Matchplay/Open was played at Olympic, Lake Merced, SFGC, the Presidio and HardingPark.
A full list is attached below.
DT
file:///C:/Users/DT/Downloads/SF%20Open%20Winners%20-%20chart-1.pdf