I own the two original slip-on hoods (Nr. 1 and 2, as I remember) from the early days for lenses from 25 mm on. They work together with the CONTAX filters (spezial diameter necessary) and look better then the actual Nr. 11 and 12, because of their form and material. I don´t remember my slides to be vinetted.
Today I mostly use the metal hood Nr. 1 with 55/86 ring and the CONTAX E55 filter. It´s big, but no vignetting with slides to notice. That´s not for polarizing filter.
Metal hood Nr. 2 doesn´t work either with 25, nor 28 mm in practise.
Slip-on filters were common until the late 70th, mostly chrom finish from brands like heliopan. Mostly without coating. CONTAX never sold this type, as long as I know.
But there is the CONTAX 70 mm slip-on filter adapter for screw-in filters at the Distagon 18mm at least.