During the first year of the Advance Design 1/2 and 3/4 ton pickup, the standard three speed transmission was a carryover from 1946. Its top loader shift lever extended directly from the transmission through the removable floor pan.
When the column shift three speed was introduced in 1948, the floor shift hole was eliminated. Therefore, the 1947 three speed floor plate has the round shift hole as well as the hand brake lever hole. The 1948 and newer column shift transmission and foot operated park brake uses the same floor pan but the holes are not punched.
Note the short metal upper horizontal stiffener on the 1948-55 pan. Because of the hand brake oval hole, it was necessary on the 1947 model. To keep tooling costs low, the length was unchanged even after the shift hole was not stamped.
1947 on left | 1948-1955 on right (above)