Out of curiosity alone I looked for these cars in my July 1947 ORER and, like you, found them gone by that time.
So I looked at the WFE and BREX rosters to see if they had anything similar, which they didn't. I had also look over
my Athearn FOBX #4156 which is listed but has nowhere near the height of your two odd balls. With no similar cars
listed for the related companies I went back and looked at the January 1938 ORER and found both listed there and
just as you described them. Sorry I can't offer any ore on these tow strange cars.
Speaking of the Athearn FOBX #4156 does anyone know where Fruit Growers Express used these cars and who
they served? Fruit Growers was a large operator in New England, especially on the New Haven, so I bought it some
time ago to add variety to a reefer block.
Cordially, Don Valentine