If you use plugins, activate the plugin checkbox and put in the description what plugin the customer needs and the version of that plugin.
If you collapse all plugins so it works in the vanilla software then you dont need to activate the plugin checkbox - since they dont need it when purchasing the model.
Think of it like anything you buy in real life. If you purchased an electric dog collar and it says 'Batteries included' then you dont need to buy batteries. If it says on the label 'Batteries NOT included' then you know as the customer, you need to buy batteries for your new product.