In keeping  some other comments, I don't find this arrangement at all unusual.  All of the pre-war (that's WWI) MDT reefers had very minimal hardware on the hatches -- a small hasp to "lock" it, and a lift handle.  The familiar latch bars only appeared on the post-war cars, and I have seen nothing to suggest that the prewar cars were retrofitted.

The early MDT cars did not say VENTILATED initially, but the photos suggest that they all did by the mid-twenties, regardless of hatch configuration.

Dave Parker
Riverside, CA