The DR 35/3 was built in 1967 and 1968. You promptly guessed wrong, but we don't need any further, superfluous correspondence because of this one year.
The types DR 35 to DR 35/2 were available from 1965 to 1968, whereby the 35/2 was 60 cm longer and therefore had a maximum of 9 instead of 8 rows of seats.
The 35/3 was created on the initiative of Swiss customers and had the OM 327 with 170 hp instead of the OM 352 with 126 hp. Six examples were built.
The DR 35 L was the final model from 1968 to 1971. “L” for Luftfederung (air suspension), 9 rows of seats, OM 327 with 170 hp, later OM 360 with 192 hp.
This is your next point