Hi Suneel,
V3 jobs are required to move the delta entries from Extraction queue(LBWQ) to BW delta queue maintenance(RSA7) only.As Amit suggested after locking the user no posting will happened.
So coming to historical data it depends on client requirement, suppose you are expecting historical data for enhanced fields also,then you need to delete data from targets.
Just follow the below link.
How to initialize 2LIS_11_* without downtime if loading is direct to infocube?
Thanks,
Somesh.