I'm not familiar with the 6x6 but there are a few old timers at the camera store I work in I'll ask tomorrow and see if they know about it.
Found this from wiki...
A range of high-quality interchangeable lenses was made for the camera. The standard lens is an 80 mm f/2.8 Tessar with preset aperture: McKeown states that lenses between 56 mm and 400 mm were made. The lenses have helical focusing, and a bayonet mount. Some of the lenses are illustrated in a 1953 edition of 'Exakta' magazine, and the article refers to
Meyer f/3.5 Primotar lenses in 85, 165 and 180 mm, and f/5.5 Tele-Megors in 150, 180, 250 and 400 mm; a rather smaller range of lenses (and only long focal lengths) is in the 1958 price list. As with other Exakta cameras, extension tubes and a bellows were available for close-up work.
Old price list...
Wayback Machine