There is a missing BP function to retrieve the previous purchases or owned items.
You just have to look at GooglePlayStoreHelper.java in the engine (16.3), it has the following 4 (four) callbacks:
- nativeQueryComplete → when asking for the different products available has been completed
- nativePurchaseComplete → when we purchased something
- nativeRestorePurchasesComplete → when we restored a purchase
- nativeQueryExistingPurchasesComplete → when we ask for the already purchased items!!!
Now if you look to BP available functions there are 3 (tree, so one less than above) groups:
1.ReadInAppPurchase, it corresponds to nativeQueryComplete.
So you cannot get info about currently owned in app purchases, just about the available ones (wich includes the ones you already own).