There is a field on the Product2 object called “SBQQ__HasConfigurationAttributes__c”. This field is one of the only fields in CPQ that does not have help text next to it in the UI.
You can see Lock Description has a help text “i” next to it but Has Configuration Attributes does not. It does have a description in the SFDC documentation though.
The description says: “Checks to see if this product has configuration attributes”. But upon viewing some bundle products that do have config attributes, this checkbox is not checked. That leads me to believe this checkbox is not automatedly filled. You have to manually check this if desired.
One thing to note is that if you do check this box and there are no Configuration Attributes defined, you will get a NullPointer exception.