I’m quite familiar with gold and gold plated Swans but I’ve never had a Conway Stewart of this type. A correspondent sent me photographs of a pen he has recently acquired, asking if I can tell him anything about it. He believes it to be all metal, not overlay. I was able to track down some late thirties rolled gold Conway Stewarts, Nos 175, 275 and 775. None of them look quite the same as this pen though its shape suggests a similar date.
The owner of the pen (and I) will be grateful for any information you can provide.