This recent discovery is thought to be a one off dial design by Singer (a major supplier of dials to Heuer amongst others) dating from some point during the early - mid 1970s. As Jack Heuer mentioned to me during research for the book, Singer and Piquerez would bring designs for cases and dials to them for feedback during the process of finalising designs. This dial was meant in my opinion to serve as a tester for the interior paint colour of the dial and sub registers. It came from Switerland via an ex Heuer & Chonoswiss servicemaster who tells that the crazy "Rising Sun" outside design was meant to both highlight the internal area of the dial that was being tested and make sure that it did not find its way to the retail market by mistake...there is certainly no mistaking this look for a production variant! The main dial is a different colour to the matt blue 1133 dial variants, being of a more grey hue and has black painted sub registers. The usual tells of script, markers and dial lume are all original and as should be.  Note the way the original aged lume plots sit on top of the outer red stripes. It will be interesting to see if any more test Monaco dials are out there?

Singer Test Dial