>>2993707 (lb)
As requested, a source for Version 4 UUIDs being random:
https: //www.ietf.org/rfc/rfc4122.txt
For UUID version 4, the timestamp is a randomly or pseudo-randomly generated 60-bit value, as described in Section 4.4.
For UUID version 4, clock sequence is a randomly or pseudo-randomly generated 14-bit value as described in Section 4.4.
For UUID version 4, the node field is a randomly or pseudo-randomly generated 48-bit value as described in Section 4.4.
If you read through the document, it basically says version 4 UUIDs are all random data, except for this '4' digit in 1st position in the 3rd group.
That said, nothing prevents a malicious implementation from not using actually random data. I don't think it is a high risk, or white hat would have figured it out already.