txs

Here is a side by side pic of the 727 O/P shafts for the 203 tc ( the short one) and then the 207, 208, and married 205 tcs. The spline count and diameter is the same, but you get very little spline engagment using the 203 shaft with a 207, 208, 205 transfer case.
http://www.pbase.com/txs/image/25970181
The 727s used behind 89 90 and early 91 2wd autos used an even shorter O/P shaft but you can identify it by the threaded end that retains the yoke, although I believe it's the same spline as the 4x4 versions.

txs

Well, you would have to have the 203 pattern extension housing to go with the 203 specific output shaft. The 203 was unique, no other tc used that bolt pattern. Then you run into problems such as 90 was the first year for the output shafts to use the small pilot, this goes in a hole in the rear end of the input shaft. 89 and back output shafts have a much larger pilot diameter than 90 and up so you can't use a 89 and earlier O/P shaft with a 90 and newer I/P shaft. To further cloud the issue there was a spline change in 76 where the front carrier splines onto the O/P shaft, so you would not want to use the shaft out of a 74, 75, 203 application 727. Clear as mud? btw, 203 use 727s are easy to identify, they had a cast iron extension housing, all other 727s use aluminum extension housings. I suppose you could use the earlier input shaft , but you always have to use the matching year input shaft and reaction shaft support, there have been major engineering changes and mix and match can be trouble right here in river city.