quoted

[...] For MBR/DOS type labels that is a pretty obscure field
at offset 0x1B8 on the disk, and it is a 32b field. [...]
GPT/EFI labels instead have 128b fields which are usually
filled with UUID-structured random values [...]

This is the output from fdisk -l where it is called "Disk
identifier":

[...]

Disk label type: gpt
Disk identifier: 00000000-0000-0000-0000-000000000000

[...]

Disk label type: gpt
Disk identifier: EF1A3010-0A15-5A4B-A6FC-1B0EA869D0A7

Reading carefully the output might help, as well as discovering
that recent versions of 'fdisk' and 'gdisk' handle both DOS and
GPT labels (in different degrees). Using the 'm' command of
'fdisk' show it can handle also other types of labels.