Suspect this dates back to when for the sake of completion, Kadee/Micro Trains made all their couplers with all 3 extensions.
MT does not sell a medium extension arch bar. Sad, as I have had uses for one.
I had intended to use one on this:
This is a B-mann (other manufacturers/importers might have offered one similar, as well) boom tender which in another version of my non-historic railroad, I had intended to use as both a MOW and back-up caboose. Given that the non-historic is a short line and it is a MOW car, primarily, arch bars would be fitting. If I intended to use it as a caboose, it would need an end platform and railing, so I added one. This meant that I could not use a B-mann archbar truck with mounted coupler. On the other end, I could or could use the MT archbar with short extension.
It would need a stove to keep the crew warm, so I added a smoke jack. The brake wheel was missing when I bought it, at a bargain basement price, so I replaced it. The hand railing was fine for my standards at the time but now, it is slightly clunky. Still, I am not going to change it.
As these two demonstrate, the MT truck mount would have extended only a few millimeters more than the body mount that I did end up using.
I did file down the bolsters as it does appear to be on stilts in its original condition. I would have had to hollow out the MT pivot hole to fit the B-mann bolster pole. I found myself somewhat unwilling to do that. As a result, I went back to the B-mann archbars and did a body mounted MT on the end with the railing. On the other end, I simply swapped out the Rapido for a UniMate
