If it's not an original installation, and it probably is not in that truck, then location of the shifter is of little value in determining the make of the auxiliary.
You may use that info to help guess, but it is not a definitive answer.
The shifter is only connected by linkage rod(s) and therefore could be mounted most anywhere the installer pleased.

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
---All pictures---
"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-