Track Smart TV Apps


I want to track of activity in applications on LG Smart TV. The program is developed in html + css + js. I want to use http tracking Tracking API - Analytics Platform - Matomo
Q: Can I use serial number as a unique identifier. Are there any restrictions on the parameter id?

The unique visitor ID set via setVisitorId must be string $visitorId: 16 hexadecimal characters visitor ID, eg. “33c31e01394bdc63”

one more question:

if I do not assign id, how piwik generate id?
Example in the specification does not contain id. I does not specify id for tracking on mobile devices(iPhone). Statistics looks correct.