The common ID aspect is the bearing cup in the front of the trans. The Non-WC looks more like a freeze plug. The WC looks like it is machined. That said, I don't know if they are interchangeabl e e. So, the ID is probably only useful with original installations - to be safe. From what I've read the Non-WC and the WC differ only in the bearings (roller vs bronze) and the syncro's (brass vs lined). Apparently the gears themselves are similar with the exception of the aftermarket version.
The T-5 in stock form is only good for about 250-300 Ft Lb. torque. GM never put them behind a 350 Engine which I think says a lot. Most don't like the Mustang 3.35 1st gear. The preference is for the 2.95 1st gear in the GM trans or the aftermarket version. For a mild HP engine that isn't thrashed at the dragstrip they are good transmissions. Tons more info on the internet for the reading. Most hate the near 4.00 1st gear in the 2.3 T5.
I wonder if there is enough spline on the input shaft to use an offset pilot bearing (extra material more towards the trans) and use the 3.35 Mustang trans with the 2.3? One might have to turn the bearing out of bronze but it is only 1/4". A T-5 site made this comment, "The 4-cyl shaft is about a quarter inch longer than the 83-93 V-8 shaft. The difference is considered negligible, but the pilot bearings are also different sizes." Most hate the near 4.00 1st gear in the 2.3 T5.