Most FMF sparkarrestors go by the model name "Turbine Core" (as opposed to "Power Core" which are silencers, not spark arrestors). There is the Turbine Core (older) and the Turbine Core II (newer). Those two are mostly what you see on KDX's.
To decode that model number you posted, I recommend emailing FMF directly at: tech@fmfracing.com
Don't send them any attachments or they'll delete your email without reading it.