The easiest way is to go to the list settings.
The list id will be in the url.
For example:
https://someserver/sites/somesite/_layouts/15/listedit.aspx?List=%7B263FE49C%2D7FB3%2D4247%2D93CD%2D4AAB9770EF97%7D
Extract the list argument:
%7B263FE49C%2D7FB3%2D4247%2D93CD%2D4AAB9770EF97%7D
And then url decrypts it:
{263FE49C-7FB3-4247-93CD-4AAB9770EF97}
This is easy and works with the whole version of SharePoint (in fact, there is no SP2007 for testing, but I'm sure)
Steve b
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