Maybe that's a 1.9 and not a 2. I'm not sure, I'm reading conflicting stats. Anyway, it's a 4 banger diesel from '63.
The 190Dc was actually a 2.0L (1988cc). When the 200D came out in 1965, it retained the same displacement but went to a 5-main bearing crankshaft instead of the 3 in the 190Dc. The 190Dc W110 ran from 1961 to 1965. The upgraded 200D ran from 1965 to 1968. There was also a 230 built from 1965 to 1968 which had the M180 straight six gasoline engine, and of course the 190c and 200 gas models. The models are very similar with the exception of a few body, trim, and interior details. Front disc brakes were added as standard mid-year 1963, so the one you are looking at might have them.
Four on the tree was standard for Mercedes until the 200 and 200D model came out, when a four on the floor became an option. As for mileage, factory specs were 26 mpg, but 30 is doable, and maybe a little more depending on your driving.
As for parts, body-wise you are mostly looking at used, a few aftermarket (which usually fit more collectable Mercedes models also), and of course the Mercedes dealer can get some new (for a price). As for mechanical parts, they are still available from the dealer and some aftermarket sources. Being the suspension is the same as more collectable models, those parts will definitely be available. If the engine does need a rebuild, I would inquire on part prices before you decide to buy if money is an issue. Get a copy of Hemmings Motor News, as there is usually a good number of parts suppliers advertising in there.
I'm surprised nobody has mentioned rust. The bodies were known for rust in many areas, including the rear wheel arches, rocker panels, floor boards, front fenders (headlight area and lower corner), and front bumper supports to name a few spots. And if the front ends were not greased on a regular schedule, they will wear out in areas of the king pins and A-arm pivots. And the hydraulic clutch is a minor annoyance when they leak or get air in the system (usually from non-use). And like has been said, acceleration is tortoise slow by today's standard, 0-60 in around 30 seconds with a top speed around 80 mph if you are brave enough to wrap the engine up that fast. But they do drive nice once you get up to speed.