Info Needed On The German, Rheinmetall 120MM DM-38 TPCSDS-T

I am trying to find out when the German, Rheinmetall manufactured, 120MM DM-38 TPCSDS-T round was type classified and adopted for service on the Leopard 2 MBT. If anyone has information concerning this date, I would be extremely grateful. I am trying to put together a developmental timeline for an IAA Journal article :-)

Thanks in advance,