what will be the rate of GST taxes on 1bhk flat registration after 1 July

Stamp duty & registration charges levied by state revenue over property registration will not change in current tax regime or after implementation of GST........

Building ready to move as on July 1 2017 - Yes

Buyer possessed the flat as on Jul 1 2017 - No

Service tax dues pending to be recovered from buyer as on July 1 2017 - Yes

Query:

I as a real estate seller wish to recover GST from him - am i right or not?

if any article supporting the above. Pl share that too