I just had a thought, when did Mopar start with their floor shifted 3 speeds? I have never seen one in an early A but I have noticed Dusters and E bodies with them. Here's an ad for a 68 Inland shifter. Strange that I thought of this before seeing this ad.
[FOR SALE] - Inland Tool and Manufacturing ITM Three Speed A230 Shifter and Linkage
The factory installed three speed transmission floor shifter was first available in A-bodies in 1970.
The three speed transmission floor shifter became available in A-bodies, and E-bodies, and again in B-bodies, when the A-230 three speed transmission was introduced in 1970. The A-230 replaced the A-745 transmission previously used with eight cylinder engines and heavy duty six cylinder applications. The A-230 was used through 1981.
The A-903 three speed transmission used in 1960 - 1972 six cylinder and small eight cylinder applications in A-bodies and others was column shift only from the factory. The A-250 three speed transmission was released in 1973 to replace the A-903 transmission as a column shift transmission in six cylinder applications which continued with its A-390 transmission replacement used in 1975 - 1978. From 1970, the A-230 was used in six cylinder floor shift applications.
The A-745 three speed transmission was in use 1961 - 1971 in B-bodies and C-bodies with eight cylinder engines and heavy duty six cylinder applications. The A-745 was available with floor shift 1961 - 1964.
The 1962 - 1964 Max Wedge B-bodies with manual transmission used the Borg Warner T-85 three speed transmission and were available with a floor shifter. The Borg Warner T-85 transmission was also used in some 1960 - 1961 full size cars. It was used prior to this as well and available with the electric overdrive version.
There might be some other variations to the foregoing car applications.
Three speed transmission floor shifters were common in the 1930s when the relocation to the column occured.