type 4 tinware non-return flap covers

[Crankster]

Hi, I'm slowly trying to sort out the tinware on the motor but have hit a bit of snag with the two covers that go over the non-return flaps either side of the fan duct outlets. The flaps are hinged on pins and the covers are left and right (viewed facing the engine. Their orientation is important as they're asymetrical. Also, they are straight and I've reused the pins but they seem to foul on the pins and wont sit flush. The edge that sits on the heatexchangers isn't a neat fit suggesting that maybe they had a gasket of some sort under them that would have given a proper seal and raised the plates clear of the hinge pins. I hope this all makes sense? I can't find any drawings or mention of them in any of the manuals nor any reference to a gasket of some sort. I never pulled these off the motor originally so have no idea what is or isn't missing.  Any thoughts appreciated. The image below is from another site but shows them as I believe they're meant to be oriented???