There are a lot of the Cocarette variations, 68 quoted on one site!, and the variation of struts you have is in pictures on the net, but a different shutter. Has the back got multi windows? It may have done two per frame using a now missing mask in the film frame, as with 645 on 120 etc. Stephen.
129 is very, very, unusual, 129 roll film is 1⅞" × 3" format, but I was not aware Zeiss used it. Ensign made the film size themselves as they manufactured film as well as cameras, and it was made to get around 127 Kodak and Ansco patents on 45mm wide film. Measure the spool width and see if it is 45mmm or not. No chance of finding 129 these days, it would have to be slit from 120, and a black backing paper made to suit. Stephen.
129 was originated by Kodak just before WW1, mainly for Ensign, ( Houghton Butcher), cameras, who took over the size as the main user. Voigtländer used the 129 size as did Contessa Nettel, who became part of Zeiss, the Cocaratte brand becoming one of the range.
I have examined the camera minutely using a magnifying glass and find no trace of any number. I would love to find a reference for a Zeiss Ikin Cocarette that use 129 film and produces a 3 1/2 X 7 1/2 Centimeter negative. My camera does not have a frame finder or a folding optical sports finder.
You can try a pinch of white talc powder on the leather, it will clean away easily, do not get it near the shutter or lens, of course. It gathers in the patterns, numbers etc., to make them more visible. Zeiss never had really consistent marking positions, and variants are legion, they did not throw away parts, they used up the existing parts on new versions! This seems to explain the long levity of some Zeiss designs, and the multitude of variants