[Arran]

That B & O reminds me of a post war British set like a Pye or a larger Bush. One trick I picked up from some fellow restorers, if you want to preserve the original looks under an all original chassis, is to dissemble the old paper capacitors by melting out the old innards and inserting new axial lead polyester film capacitors inside the old cardboard tubes. You can then seal up the ends with hot melt glue, preferably the brown kind. There were a few U.S sets that used variable IF bandwidth, American Bosch and Philco being two examples, perhaps a few others but it wasn't common. Bosch used a mechanical system to control the bandwidth, Philco used an electrical system.
I see that the B & O uses Phillips/Mullard style metal spray tubes, with a side contact base rather then pins, those were almost the industry standard in many parts of Europe during the late 1930s and 40s. Some Canadian Rogers built sets used a very similar idea, but the coating was thicker and it was usually grey or black, and the tubes used North American style bases such as octals.
Regards
Arran