the USB includes updates?
Yes and no. Microsoft does update the ISO if they so choose. If you happen to be someone who keeps their ISO collection, and has downloaded them at different times, you can check this out.
The other day on another venue, someone asked if there was a way to find out what version of Windows 10 was associated with a given ISO that had been put on bootable USB media. Here was my answer:
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Yes. But unless your memory for which build number goes with which version number as time marches on you're going to need to consult a page such as
Windows 10 version history - Wikipedia or Windows 10 Version Numbers & Build Numbers as one step in the process.
On the bootable media there will be a file called setup.exe, which is what you run to install or upgrade Windows 10. If you open the file properties for that file then take a look at the Details tab under properties, you will find an entry for File Version which is of the form 10.0.{insert build number here}.{some single digit}. So, the setup file that has File Version 10.0.10586.0 is the installer for the Windows 10, Version 1511. The setup that has File Version 10.0.15063.0 is the installer for Windows 10, Version 1703. The setup that has file Version 10.0.18362.1 is for Version 1903. You get the idea.
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If one mounts the ISO as a virtual DVD the same check can be done on setup.exe.
I know that I have had ISOs for the same major Version/Build number where earlier downloads had the .0 suffix and later ones the .1. I'm almost certain there were more than that for Version 1809, but don't have the time to check at the moment.