I could be wrong but I'm pretty sure the high texture pack required going through workshop. If this started automatically it's probably a patch.
No, that's offered as a free DLC, which means it will download automatically every time the game installed. I copied the plugin and BSA files to an external hardrive, but even after copying them to the Data folder after install Steam insist on downloading them (which is weird because that works perfectly for New Vegas' DLCs

). And since you can't remove a DLC from a game either, that is a required part of of the installing process from now on for me, despite me not even having them activated due to them being too much for my PC

Though if memory serves, it's size was around 2 GB. When Steam seems to be starting a humongous download, i pause the update and make it check game files, that corrects the download size.