There is no such thing as a specific crossmember for each t-case. They are separated by the years.
Up to '84 are all "flat" crossmembers like the pictures show. But the '81 to '84 crossmembers are flat and look a little different than the '80 and older members. Either will work as both are flat. The 203, 205 and 208 t-cases were all employed on these flat crossmembers. All will interchange with the other.
The '85 and newer crossmembers are a different design. They look like "double humps". You cannot use an '84 or older t-case adaptor on the '85 and newer crossmember.
1 ton crossmembers up to '84 are flat but different as they are shorter in heigth to compensate for the frame height. Again, the 1 ton members will not work because they will put your t-case up higher if you use one on anything other than a K30/3500.