How are is custom post type “product” being indicated as “available”?
If you’ve not done this yet, consider also making a custom taxonomy “availability” for your custom post type “product”. This is so you can create a custom taxonomy term “available” you can associate your products with.
You then go back to the WPSP edit list page and set the post type to “products”, set taxonomy to “availability” and tick the term you want to display(in this case, “available”). https://share.getcloudapp.com/L1uODXo1