Beverly package shelf

You are correct. That's what you get after a long day and you try multitasking while typing without proofing!

Everything would have been worked out in the drawing office before the first Beverly started on the line. This agrees with Rick Hulett's comments.
The supporting sheet metal being common to both the Westchester and Beverly.

I assume by Cab you mean Cabriolet.
Just a note--Cab has no shelf ,Phaeton does

I finally found the time to access my 37 Beverly where it is buried in storage. I pulled some dimensions off of the shelf. The for/aft dimension on the shelf is 18 7/8 not the 21 1/4 which defines the Westchester shelf length. The left side shape does not have a rounded corner like the Westchester but starts to curve and then stops to match the approximate 30 degree line of the hinged part of the shelf. The hinged portion of he shelf has a max width of 29 3/4 inches and a length of 10 7/8. It ends 3inches from the cutout for the gas filler sleeve. When swung upward, it just touches the upper edge of the trunk opening. The 3 1/2 inch wide block on the bottom side swings down and should touch the spare when installed .
The car is squeezed in a really tight spot and making the measurements was difficult but the should be good to about + or - 1/8 inch.

As Rick Hulett would say, you have to think production. The Westchesters were the first group produced in mass. They had the shelf to fit it. When they had a Cab or Bev they took what they had for a shelf and modified it to meet the requirements of the newer model. In the case of the Bev they basically trimmed the rear shorter and added the hinged portion. For the Cab they made a semi circle cut out at the forward edge to allow the rear window room the the top was down. When they went to a larger rear window on the Cab., they made the forward cutout larger.

The hole pattern looks to be the same as that on the Westchester shelf drawing which is to be expected. Gary you can use my drawing and simply scale off the hinged extension in this picture.

Photo of original Beverly package shelf