91 Gt Convertible Computer ?

Hey guys brand new here. I recently picked up a 91 GT vert 5 speed that needs some work. I have owned 5.0 fox bodies in the past so I know my way around them pretty good.
My question is why my car has a ECU that links its part number to a hatchback 5 speed model? When we went to order a new one last week the convertible part number was different than what I pulled out and was in fact a hatch, 5 speed car with the "AA" at the end of the number.

Can someone shed some light on the differences and what will work for my vert car?

Thanks!

Thanks, that's what I thought. It was weird though when we looked it up in the parts guide at my buddies auto shop as it gave us the A9L but had different part numbers for each. And the vert one was more expensive by about 30 bucks.