The steps used for a part model inside the product are also applicable here. Please refer to Working with part models page.
Where is my product part?
However, as mentioned above, if you choose to delete the catalog part model, then all the product models created based on it will also be deleted.
How are my parts connected?
Forgot how your product parts are connected to the catalog ones? Click on your product part and expand the Information tab, which is on the right side. The field 'proxies' tells you to which catalog part is linked to. If it is empty, then it means that the part has been created straight into the product.