Detect if the user is a new customer or an old one in shopify additional scripts

Question

I am developing an affiliate pixel script to put in the additional scripts sections of a Shopify shop.

I should calculate the commission to be given to the affiliate based on the state of the customer. I will give the affiliate different commission if the customer is new or old.

Is that a way to detect if the customer is a new or an old one in the additional scripts sections of Shopify even if the customer is not signed in?