The mirror mounts on a single, long arm (tube) with a bracket that bolts onto the body at or near the upright that runs just ahead of the door. "Hot-shots" used more substantial mirrors mounted on both sides that fastened to the top of the door and near the low part of the window. I think the single-armed one is "original". You can buy replacement mirrors at any auto store.

In fact, I have one from my '51 truck. I changed my bed to a narrow design and am using the short-arm mirrors used on pickups.

I'd be glad to send you mine if you want it. $10 should cover the shipping and some. Let me know.

Dave

David C. Baker