Back in 1999 (Volume 3) MTH catalogued a die cast caboose in the body style that is the same as these cabooses. Product number 30-8502 C&O. I assume they also offered it in NYC at some point. My friend collects the Railking diecast line that MTH once had. They are really cool trains and he has a nice collection of them.
That is exciting news to hear about the upgraded details on these cabooses.