Here are all the different Red Submariner dial variations that appeared in the 1970s. Missing from this list is the first iteration of the Red Rolex Submariner dial, the MK1 dial, however, this is because they were produced in the late 1960s rather than the 1970s. It is estimated that these variations of the “Red Submariner” dial would appear on the reference 1680 replica watches until around the mid-1970s. Thereafter, they were replaced by dials featuring all-white text.
1. Red Submariner MK2 dial  
The first MK2 dial appeared at the beginning of the 1970s decade, as did the MK3 dial, which had an almost identical overall appearance. However, there are subtle differences between these two variations of the Red Submariner dial. The MK2 dial is of the meter-first variety and will have the name “SUBMARINER” printed in red over white.
2. Red Submariner MK3 dial
The red Rolex Submariner MK3 dial from the 1970s is very similar to the MK2 dial, also of the meter-first variety, open six. However, the red “SUBMARINER” text on the MK2 dial is printed on top of the white, while the MK3 dial will be printed directly on the dial surface.
3. Red Submariner MK4 Dial
The replica Rolex Submariner dial is the earliest version of the footprint, first appearing in the late 1970s and continuing to appear over the next few years. the MK4 dial features the word “SUBMARINER” printed in red on top of white, along with the very distinctive open six for the depth rating.
4. Red Submariner MK5 dial
Like the MK4 version, the MK5 Red Submariner dial is of the footed kind with open six hands, although the MK5 dial has fewer open six hands compared to the MK4. Unlike the MK4 dial, the MK5 model has the name “SUBMARINER” printed directly on the dial face in red, without the white backing. In addition, the MK5 dial has been in use slightly longer than the MK4, despite the fact that it first appeared at a relatively similar time.
5. Red Submariner MK6 Dial
The MK6 dial is the last red submarine dial to be equipped with tritium hour markers. Like the other later Red Submariner dials, the MK6 is of the footed type and, like the MK5, it features the red “SUBMARINER” name printed directly on the dial face without additional white backing.