Yes! As long as you integrated your store with Modalyst with the currency of your choice after April 5th, 2017 all products you add to your store will have the price automatically convert to the price you set on your Shopify/BigCommerce store.
If you just integrated your store but haven't made any changes to the products you added, you can simply uninstall the app, set your currency on Shopify and re-install the app to have it convert the price of all your products. Please do not do this if you have made extensive customizations to the products in your store already.
If you've made extensive changes to your store but would still like to convert your currency, contact us at firstname.lastname@example.org and we will make the change for you without overwriting any of the changes you made to your products in-store.