Is the product type book recommended as the only way for building a bookstore? I notice in the README_main_book_install.txt that it talks about a few core files being replaced. What implications does this have for zencart upgrades and code maintenance? Will upgrading ZenCart overwrite these changes?

Also, I couldn't quite understand the difference between ADMIN_PATCH_SQL_EXTENDED_BOOK_TYPE_V3.txt and only_use_the_patch_for_FULL_V3_install.txt

I am installing this for the first time, so I am not sure which patch to use.