From Sotheby's:
• Ref. 4830 MVT 495802 CASE 335589, Antiquorum Geneva, lot 724, Oct. 21, 1995,
Each of the dials in this series of watches appears to have been produced by Beyeler, a competitor of Stern Freres and Singer dial makers. Beyeler produced dials of all types including cloisonné dials on special order for major Swiss makers including Vacheron Constantin and Rolex. In 1997, Beyeler was purchased by Rolex.
The art of cloisonné is rarely seen on a Vacheron Constantin and surviving examples show the attention to detail offered to each of these timepieces. In order to produce one of these masterpieces, thin gold wire is first carefully placed on a primary layer of enamel. The enamellist then carefully mixes glass and oxides to create the perfect color and places the enamel on the dial. During this process, the enamel is fired up to 7 times to achieve the perfect balance of color and stability. The art of the enamellist is the ultimate expression of patience and discipline.
ref. of Antiquorum Geneva, lot 724, Oct. 21, 1995 ,that is the question.