Gear ratios for '83 and '84 Non WC T-5 boxes

Ok guys. If anybody would know, this is the place to ask. When it comes to the '83 and '84 T 5 gearboxes, most of the information is the same except one factor: The 5th gear.

I've read on Modern Driveline where it says the '83 1/2 and '84 both had a .63 overdrive ( Modern Driveline - T5 History in Ford Mustangs with specifications for World class and non-World class T5's bottom of 2nd paragraph), but another like CarCraft mag where it says 5th for both years is a .72 ( T5 Transmission - Car Craft Magazine ). I also get conflicting pages like the Mustang GT registry where it says one gear for one year and a different one for another ( 1982-1993 Mustang GT Registry - Summary of Transmission Info ). I've pulled a transmission for each Mustang year but no tags are included. I intend to use the one with a the .72 rear for a project, but have no idea which has it if either even does.

ACK! anic: Can someone set the record straight?

The '83 1/2 box is out of the car and sitting on my workbench. Can I open it up and count teeth to determine what the gears are? I've read about it, but i'm not sure what i'm looking for.

Sadly, no tags are on either gearbox.

The only reason I can best guess what they are is due to the year of the cars the boxes were pulled from. I know the one I have on the bench is a Non WC due to the brass rings I found when I pulled the input shaft out for machining.