It seemed like it was a flat washer but I'll get some of those Dash o-rings for the next filter change. For the filter bowl I checked for a manufacturer stamp but couldn't find one so now I'm stuck on that bushing.
The fuel filter assembly has three kinds of gaskets.
Top to bottom:
1) the thin outer o-ring between the outer bowl and the filter mount.
2) the thick, wide inner gasket/washer between the filter and the housing, (usually comes with the filter)
3) the two, small o-rings either side of the spring on the bolt. (Dash 202)
Are you talking about the large flat washer on top of the filter that should come with the filter, or the two little ones?
You may have a different filter assembly than me, but the anodized red filter bowl looks the same to me. It is also possible that what you have is something different.
FWIW: The dash 202 o-rings have an inner diameter just smaller than the bolt shaft.
From the -24 manual;
All the best,
2Pbfeet