I have 4 mid sections. 1 80s vintage 4 drawers that is similar to that yet painted like that base cabinet. A 2 drawer from the 2000s that is a full 16" depth front to back. And 2, 3 drawers I just picked up from Blains in the last year or so. All are painted yhe same.
Note the cut out on the bottom left and the associated tab on the top. That is for a locking bar. I expect it is from a budget or lower priced line of boxes and could very well be the original paint scheme.