Well, this is turning out to be a very interesting car. Why? Because I can't figure out where it came from...
I know of two pictures, taken moments apart, by Tom McNamara in New Britain, 1956. One is in Trackside with Thomas J. McNamara, pg 98, the second is in New Haven Railroad: The Final Decades, pg 132.
The second picture is just the end of the car from the side, but the first picture is a nice 3/4 view with only a section of the end hidden by 0802. The end sill matches the Westerfield kits, not the NHRHTA/F&C kits. The end is still a double-sheathed end, but with a horizontal steel strap across the entire end. It does not have the corner bracing that is found on the Westerfield kit. It appears to have received a new steel roof (I'm guessing a Hutchins Dry Lading roof, with the small 'riblets'). It also has an Ajax power hand brake.
The ends have ladders, the sides - drop grabs. It has double sill steps like the Westerfield kit, not the rebuilds represented by the NHRHTA/F&C kits.
But it has a straight side sill, and from what I can tell, a straight center sill. This matches the NHRHTA/F&C kit. The position of the poling pocket is like that of the single sheathed end rebuilds in the Mainline Modeler articles (July and September 1988). But these cars did not have the steel strap across the end before rebuilding, and they received single sheathed or dreadnaught ends.
From the prototype information in the Westerfield kit, I'm guessing it was converted to work service in 1945. The double sill step under the door was probably added at the time it was converted. But it does not seem to match any of the documented cars. I'd like to find the 1945 Equipment Purchased, Converted, Destroyed or Condemned documents. If it was converted then, it should have the original car number.
In the meantime, I'll need to shave off a few more details from the Westerfield body. The F&C underframe is too small to fit the Westerfield kit. So I'll file down the fishbelly understill instead. The fishbelly side sills are separate parts, so I won't need to use those. I'll keep looking for an appropriate roof, and see if I can dig up more pictures/information.