Hi Jack
I also have a ’49 with the layout you describe. The panel lights are controlled by 1 of 3 switches in a row either side of the starter button on the bottom RHS. How original that layout is I don’t know and I can’t check the photos in the period road tests I have as they are away in storage.
Yes, there was an advance/retard centrally located beneath the oil pressure switch. Mine, along with many others now has a temp gauge located in that space so cannot provide a photo.
Cheers
Jonathan
Jonathan