Added this 19004 M90 to the collection earlier in the week. My first non-traditional-case shape watch. Waiting on a strap for it as these have 17 mm fixed and curved strap bars (hard to say spring bars or fixed lugs when there are neither springs nor lugs...).
Per the discussion earlier in the thread, these disco volantes (-04 case number) are also not FB/Taubert cased. Same goes for the triple-step bezel cases (-05), the cases with vertically stepped lugs (-23, -33, and -43; like the one that Arthur/Shuck the Oyster sold a few months ago), and the skinnier lug ones like
@Ponthelion posted above (-26 and -36); these case styles are only some of the snap back case styles that housed the M90/95. The FB cases were the only screw back variants, I have not seen that any of the snap backs were FB/Taubert signed. The dials in FB/screw back cases tend to have aged better because of their better water resistance, though there are obvious exceptions to that general trend.
The hunt for more pulsations M90/95s continues. My goal is to have one in each of my favorite four case styles: -08 (565 case), -04 (disco), -48 (faceted lug), and -28 (triple-step). Two down, two to go!