The Enigmatic Car (Unrecognized Mercedes)

It is obvious that our today’s hero belongs to the family of Mercedes-Benz, but I find it rather difficult to make a deduction exactly which model it is.
The exact year of production of this "mysterious" Mercedes is unknown. The owner offered his version, but, having carefully examined the car, I couldn’t come to a certain conclusion on the production year.

The reason for that is that the car has undergone numerous changes at the hands of its previous owners. Before appearing in Armenia, the car must have been carelessly used somewhere in the Soviet Union after the World War II (I am more than sure that the car was brought to the USSR as a war trophy from Germany like many other retro miracles), and then it was shamelessly equipped with details and spare parts taken from soviet cars, so it altered beyond all recognition.
However, after much research, I found that there was a similar model manufactured between 1932 and 1937, which had various body modifications: a sedan, like our undiscovered hero, the Pullman (the elongated version of the sedan), coupe-cabriolet, “landole”, etc.

At first glance, our hero bears a strong resemblance to Mercedes-Benz 200 W21, which was first introduced at Berlin Motor Show in 1933, but at the same time, it also bears external resemblance to 260D model, which was also introduced at the same motor show as the first passenger vehicle with a diesel engine in 1936. I also learned that the 200 W21, in spite of being produced in large quantities (15622 samples), didn’t play a major role in the history of the German car manufacturer.
As for the D260, it was a “trailblazer” in the world of automotive industry. In the mid-thirties of the last century, not many people believed in the success of passenger cars with diesel engines, but time has shown quite the reverse- every second vehicle runs on diesel fuel nowadays.

When I found out that the first diesel engine car was built on the chassis of the 230 model, which was subsequently built on the chassis of the 200, I only then understood the reason of the similarity between our unknown Mercedes, the 200  W21 and the 260D. The 200 W21 was the most affordable and fuel-efficient car of its time, and the 230 was the petrol engine modification of the 200 W21.
It is impossible to even guess which engine the car was equipped with, diesel or petrol, since it underwent not only numerous external changes, but also external. There is nothing left from the original chassis either.
One thing for sure, this car belongs to the family of Mercedes-Benz, the members of which have always been the tops.