FTA benefit for a sub part imported - Customs - Exim - SEZ

ABC in India got order to supply certain Final Units to XYZ In India. ABC shall be importing two parts namely (a) Unit-1 (2) Unit-02 from its affiliated companies, located outside India. Unit-1 will be imported from Korea and Unit-2 will be imported from Vietnaam. The components shall be assembled at XYZ location to form a Final Unit. The Company classified the said parts in the heading appropriate to the function being performed by Final Unit and the HSN for the same is 851762 . However, if each part were to be imported individually, not for the purpose of assembly into a Final Unit, they would be classified under different HSN codes: 851779 for the Unit-1 and 851779 for the Unit-2. ABC is currently meeting the FTA conditions under India Korea CEPA for Unit-1 and not for Unit-2. Whether the Company can claim exemption under the said FTA for Unit-1. Is there is any risk in this transaction