fusion drive

Go to the Apple > About my Mac > System Report > scroll down the Hardware and click on SATA. A regular drive will have one entry and the size shown below; a fusion drive will list a regular HDD and an SSD. Mine has an HHD & SSD but they have not been set up as a fusion drive:

So you should see a 1TB HHD and then a 24GB (maybe 128) SSD

Your screen shot is only showing the bottom part of the report, above it you should see the Serial-ATA Device Tree that lists the drives.

As you click on each drive the report below changes to detail that specific drive. Above you can see the two physical drive that make up the fusion drive, the SSD and the HHD.

If your mac only has one drive in it, the device tree would only list one drive:

Can you post a screen grab of your device tree?

By default when you open the SATA tab the report for only the first drive is listed below. You don't see the report containing info on both drives together but separately.

No, I'm afraid you're right. It only has one internal drive, the 1TB HHD. A fusion drive is made up of two drives which would be listed here separately, although in the finder and Disc Utility you would see them combines as one.

Also, if you open Disk Utility your internal drive should actually say "Fusion Drive".

According to the report you posted (the photo I can see) this Hard Drive (ST1000DM003) is HDD not SSHD/ Fusion Drive.

That is the spec for one of the drives – in your case the HHD. Just above that you should see the Serial-ATA Device Tree that lists the drives (like in my screen shot). What do you see there?