I have spotty info on late 90's valve bodies. I'm showing a split in late 2000, see attachment.
The upper half of the trans has more or less clutch plates based on engine power, this shouldn't be an issue but I haven't mixed and matched.
There is a separate trans controller for these, is isn't part of the engine computer. In theory you could use the TCM from the donor car but electronic programming being what it is, I can't say what will work with what.
When these trans were introduced in 96, there were quite a few of updates and valve body along the way. If you use the valve body from current car on another trans you should be safe.
Places for info , ATSG is pretty much the place for aftermarket trans info, they get info from real shops and don't just reprint a factory manual.
$ 30 rebuild / general info manual
https://www.atsg.us/atsg/import-manuals-1/mercedes-722-6-nag-1.html
$ 125 in depth manual , says it has detailed info + CD
https://www.atsg.us/atsg/import-manuals-1/mercedes-722-6-dvd-video-companion-manual.html