Oh, for the golden age of spycamera watches: 1970, when spy-watches were as thick as a brick and twice and shiny:
This particular one is of the Quartz age, a 1970 SIPE LED digital watch with Steinheil 2.5/12mm lens, for 7 exposures on special cassette. Actually, it appears to be a Dynamic Scattering Liquid Crystal Display, the earliest form of LCD developed in the late sixties.