308 Single exhaust exit point

I have just sourced and bought a factory original single pipe for my 308. It was removed from a low mileage two year old 308 back in the day by a well known UK racer as he constructed his race car. The exhaust was put at the back of his workshop and hey presto he came across it recently and I have now bought it. I have been looking for nine months and they are almost impossible to locate, so I am really pleased.
Currently my 79 car has an aftermarket 4 pipe box, and the hole has been filled in. Can anyone who has the original single exit in the rear valance please take a couple of close up photos so that I can see what the outer edge finish is like when I dig out the filler and recreate the single exit. Looking from inside the rear panel I can see where it has been filled, but not sure about the detail.
Many thanks.

 

Thanks Emile

 

Thanks for your time Phil. Very helpful and much appreciated.