question

No, but all you would need to do in our ReferralCodes sample (https://github.com/PlayFab/PlayFab-Samples/blob/06a887c04068091daaf9a8610d8f32092484b4e1/Recipes/ReferralCodes/CloudScript.js) is add that property to the call. So change this:

    var UpdateUserReadOnlyDataRequest = {
        "PlayFabId": id,
        "Data": {}
    };

To this:

    var UpdateUserReadOnlyDataRequest = {
        "PlayFabId": id,
        "Data": {},
        "Permission": "Public"
    };