Yea John that's a great question. IMHO this mark was used on both Rohm's and non-Rohm daggers. Shortly after Eick switched over to the small oval for Rohm's.
My thought is that this 'large double oval' trademark is the second* earliest trademark used by Eickhorn on SA daggers.
It is found in both smooth and serrated tail versions, both with and without the Rohm inscription. As Paul says above, Eickhorn soon switched to the small double oval trademarks.
* The earliest was the small single oval squirrel with CE underneath that was found on the prototypes with the pointy wings
The same is true of SS daggers except no known prototypes have turned up.