For your future reference, each license is for a single user for up to computers, such as a desktop and a notebook system or a work and a home system used by the same person. The license is absolutely not for two users. If you need to license Adobe software for four users (the case you've implied with your posting), you need four separate licenses, although each of the four users each with their own license can install and use the software on two of their own systems.
I don't believe that Adobe Support can provide information to you as to which physical systems have which serial number used for installation. (With the current Creative Cloud software, the account information available to you when you logon to Adobe's website with your Adobe ID does show the system names associated with which activation and allows you to deactivate from the account web page. This isn't true with the older perpetual license products including Acrobat 9).
- Dov