Stock 5 speed?

No 5-speeds stock in the MII. Like you said, it was either a knob swap or tranny swap.

If its a T-5, the shifter should be nearly touching the dash in 1st and 3rd with a Fox Mustang shifter. There should be some evidence of the shifter hole having been opened up toward the dash 1-2 inches.

If its really a T-5, you'll want to pass if the engine does not match yours as the T-5 input shaft is specific to either the 302 or the 2.3L in both length and diameter. A T-5 can be used with a 2.8 V-6 but will require significant fabrication.

I'm not aware of any Ford 5-speeds until the T-5.

GM used a 5-speed in the late '70's on the Monza and Sunbird 4 and 6 cylinder cars but I don't think it was a T-5. Doug Nash 5-speeds were popular in the late '70's and early '80's, but I've never seen a Ford application.

Ford's closest thing was a 3+1 OD transmission called the SROD based off of the Top Loader 4-speed.