This is an unusual scale car. The single searchlight car is not what you would call rare but it does not show up every day. This one, on the other hand, might best be described as "rarer than rare".
There is no listing for this car in any of the books that I know of, and, it appears to be legitimate.
This is the kind of "find" that makes Marx collecting so much fun!

(Courtesy of Bob Rosenberg)