Hi Surya,
As both 100 & 120 are DEV clients, you try to copy the changes using transaction SCC1 (use SCC1 for transport request between different clients of system.), then check in ECC 120 client using transaction RSA6, you find your data sources. As you are having data in this client and it is LO data source, first fill setup table (use transaction OLI1BW for 2LIS_03_BF) for the data source and check in RSA3 at last, you will see all historical data for this data source.
Regards,
Sreehari.