The sprag normaly does not do any damage as it is pretty contained.
You should still be able to get just the sprag but it will have more rollers on it.
The valve body is probably not an issue. The spring that breaks is easily repl.
All the updates where for shift quality. If you wanted to run a newer valve body you can. Just keep the large nag valve body in. They will all work.
The control unit updates were simply for matching the modifications in the valve body for shift quality. At the dealer I have done many combinations of repl. valve bodies and control units. There simply might be some harsh shifts at certain parameters. Which MB never actually perfected it before discontinuing it.
If you do end up getting a new trans in the future get the newest unit you can get your hands on no matter what it came out of as long as it was a v8 v12 etc. Swap the bellhousing and go.