Rolex GMT Master 1675 Long E
Rolex GMT Master 1675 Long E is the first mark of the 1675 matt, called this way for the peculiar shape of the E in "ROLEX" on the dial.
Batch of production
From serial number 1.6* (1967) to 2.9* (1972).
The dial is recognizable by the E in "ROLEX": the line in the middle of the E is elongated and it is as long as the upper and lower lines. This dial is produced by Singer.
Tropical or brown
Some watch of this batch could have the dial turned brown.