You can store the ISO in a folder with that information in its name. You can designate name the ISO with the version and date in the name. It is your responsibility to document your ISOs, not Micorsoft’s. So the date of ISO creation can tell you which version (but not necessarily Build) An ISO created after the release date (before the next release date) is the version current in that time period. An ISO created with the MCT before the release date of that version contains the previous version.

There is a release date for each version of Win10. So when you use the ISO, or its created installer, there is a good chance that it will be the right version (20H2), but the Build will probably not be current (as in containing the latest month’s updates). MS doesn’t put together new ISO material for download every day. In other words, today (on 3/16/21), the ISO might contain the November Preview Build (19042.631) instead of containing the current updates for March Build 19042.867.

It will be the material from the last time MS created an ISO. However, the material (files, code, whatever you want to call it) that the MCT downloads from Microsoft to create the ISO, may not be the current build. The MCT is just a tool to download and create an ISO. In other words, today (on 3/16/21), the MCT will create an ISO of version 20H2=19042. The ISO created by the MCT you download will be the Version of Win10 that is current on the day you run the MCT.

Windows 10 pro media creation tool 2021