This auction is for one upper body casting for a front fender light produced by Guide Lamp division of General Motors.  The part number cast in the housing is 924766 and I believe this is correct for a 1940 Cadillac, but please check to be sure before bidding.  Overall length is 14 3/8 inches and maximum width at the mounting flange is 2 3/8 inches. 

I believe this is a new part, but I it was not in a box so I am not certain.  If it has been rechromed this was a good job as the details remain very sharp and the style lines look crisp and correct.  The chrome finish is excellent and there are no visible marks or damage except for about a few very small bubbles and distortions at the seam above the lower flange which you can see in the last three photos.  The seam roughness may be a factory issue or may be due to small pits which were not properly filled if the part was plated.  This part may require refinishing in the area along seam and replating to be perfect, however in my opinion the part is very useable as-is and it requires critical inspection to notice the slight imperfection.  Please study the photos closely.

This is a nice original part for your 1940 Cadillac.