Thank You Suman Chakravarthy K& Prashanth Konduru for helping me in this process.
We have raised OSS with SAP on this & SAP confirmed that we can't migrate stadard web templates which delivered by SAP & also we can only use the migration tool for the customer developed web templates to migrate from 3.x to 7.x.
Once again Thank You Guys
Thanks & Regards,
Anand