I bought a Drake from a local landlord with an extra, new in boxes for $100. The tank is an EcoDrake ST743E, but I now realize the bowl is not the ECO bowl (C744E) but rather than standard Drake bowl (C744S). It assembled fine, works fine. Bowl is labeled 1.6g but the tank controls the flow, so....Any issues here? Do I need to replace with the ECO bowl?