IPv6 Unique Local Pseudo-Random Global ID

According to RFC 4193, Locally Assigned Global IDsMUST be generated with a pseudo-random algorithm.
When working with Unique Local IPv6 Address, how does the one keep track of the entire IP address within a private network (as in not connected to the internet). Especially, as one of the criteria to meet RFC 4193 requirement is obtain the current time of day in 64-bit NTP format, among other parameters.
Do the IPv6 capable devices already have a functionality to verify global ID portion (40 bit) of the IPv6 address? Any clarification would be great.

A post was merged into an existing topic: IPv6 Address Types