I thought there was an "outer" and an "inner" snap ring groove, one of which is used with auto's, one without? I thought at one time there was some question as to whether you could put manual (factory) hubs on certain axles that came originally with auto hubs. Could be mistaken, I just seem to remember that from a long time ago.
If they used the same grooves, my mistake, no biggie, just seems odd that auto hubs (that sucked so bad) were the norm in a truck that still ran wing windows, didn't have a digital radio available, AC was optional in, and so on. Seems like a luxury item more than manual hubs, but then again, maybe it cost GM no more money to throw the crummy auto hubs on the truck.
I could almost see it as a warranty issue, but if you took it out of 4wd but didn't back up, you'd still run with the hubs locked all the time. Guess maybe GM could have figured that people would remember to back up more than they would remember to get out and unlock them. /forums/images/graemlins/confused.gif
Service manual shows a different 205 for the auto hubs as well. One other reason to stop using both hubs at the same time, GM eliminated another transfer case.