For those looking...
F100 Ford Truck Long Arm Towing Mirrors 1953 - 1966 - Set - No Reserve | eBay

 

Not bad if the glass is good.

Was looking before but wife wants to sell it.

 

Mirror head does not match the factory original.

 

The mirror arms are not original to 53-56 trucks. The 53-56 mirror arms can be extended. They have a bright finish tube that slides in and out of the outer black arm. This type of arms are from 57 to mid 60's trucks I think. The door brackets are the same and the clamps at the base of the tube are the same as the 53-56 style.

 

The 5" x 5" mirror head (B7CZ-17723-B) used with 1957/66 telescoping/non telescoping mirrors has the stud offset.

So the mirror head shown in this ad is not original to any 1953/66 outside mirror, are probably Western Auto and etc. replacements.