I assume the first six numbers you posted are above are actually
722.370
I don't know if that is correct though - can you find these numbers written on the casing just above the oil pan on the right hand side of the transmission?
If it is indeed a 722.370 then I am unable to get very far for the part numbers for you. This is all I have =>
http://mb.ilcats.ru/part/class/1/ccode/1/cat/09T/type/722/subtype/370/group/27/subgr//vers//imgno/9
which doesn't help at all.
If you happen to be somewhere in the US of A you can get free access to the EPC via
www.startekinfo.com (don't get confused between WIS which costs thousands of dollars and EPC which is free)
Otherwise you need to get in touch with the site sponsors or go and see a Mercedes dealer.
Googling the valve body part number comes up with this
TRANSMISSION VALVE BODY Mercedes R129 500SL 1991 91 92 93 for sale - Collectorcarsforsale.com