How?? I've talked with the owner before, I think he has a tin hat in the glovebox.
The testing could be for anything. There were lots of test vehicles. Sometimes they were used for minimal testing, but more for evaluations and as pool vehicles. We often had 8-10 M-plate cars in a department.
When a plant called with an issue, (say noise in 3rd gear under decel), you wanted a vehicle to evaluate it. I bet Saginaw had more manual trans cars for pool cars than most departments.