Hi,

If you want to use the template library that they have made, yes.

Please read below:

Plugin updates:
Like any premium themes on the market, the premium plugins that come with the theme cannot be automatically updated and you don't have access to the plugin's author helpdesk. Every time a new version of the plugin is released, we (the theme author), need to carefully test the plugin and fix issues if any problem arises. Then, we release a theme update that will include the new version of the plugin. It's the way it works with every other themes that include these plugins.

Plugin activation & Licence keys:
Sometimes, a plugin may ask for a Licence Key to "activate" it. Well, you don't need a licence key to activate or use the plugin! Licence Key is needed only to enable the automatic updates, access to premium support and some extra add-ons provided by the plugin's author.

If you are interested into automatic updates and premium support, we recommend that you buy a personal licence of the plugin on codecanyon.net

More info:
WPBackery Page Builder: https://kb.wpbakery.com/docs/faq/can-i-update-wpbakery-page-builder-if-i-have-purchased-it-in-a-theme/

Revolution Slider / Essential Grid: https://www.themepunch.com/faq/update-plugin-packaged-theme/