The fourth letter of the second part of the product code (after the dot) on the box should tell you whether it's a WBC or WBE model. IIRC if it's P or W it's the newer WBE panel and if it's Q or Y it's the older WBC panel. Google these to be 100% sure as I'm only recalling from memory.
pretty sure from memory that got disproved early on with some P and W codes still being the old panel.