I you want to find the guid (id) of an entity record in CRM 2013 do this:
1) Right-click the record in a list, for example a Contact, and select “Open in a New Window”.
2) The URL of the page will now display in the address bar. Copy the URL to notepad:
3) Now select the text between “&id=%7b” and “%7d&newWindow” since this is where you’ll find the GUID: 4362F996-893C-E311-9B5D-6C3BE5BEEF3C