Yes you can. Just add a tag called spreadr-hidden to any product you want. 'Add to cart' button will not be replaced with 'View on Amazon' button.
You can also add spreadr-hidden tag by default to all products you import from Amazon via Shopify. To do this simply, go to Dashboard --> Settings --> Default Values and add spreadr-hidden in the Tags input box.
Detailed instructions on how to add spreadr-hidden tag can be found here.