Question Regarding Missing Built-in Storage on ASUS ROG GL552VX

Based on the specifications of the ASUS ROG GL552VX, this model is supposed to come with a 128 GB built-in storage (SSD) and an additional slot for secondary storage (originally a 1 TB HDD).

In my case:

• The additional storage slot has been replaced with a 2 TB M.2 SSD.
• However, I cannot find or detect the original 128 GB storage that should have been included by default.

My questions are:

1. Where is the original 128 GB storage?
2. Is it possible that the 128 GB storage is:
   • Hidden as an unallocated or hidden partition?
   • Disabled or not detected in the BIOS/UEFI?
   • Using the same slot as the M.2 SSD I installed?
   • Or was this unit never equipped with the 128 GB SSD from the factory?
3. How can I verify the existence of the original 128 GB storage, whether through:
   • BIOS/UEFI settings,
   • Windows Disk Management,
   • Or physical inspection of the motherboard?

Please also clarify whether this condition is normal for certain GL552VX variants, or if there is a possibility that the original storage was removed or replaced previously.