Steve, the American 919 did not have cats until '05, I think. I know my '04 did not have one.
If you have a cataliyc converter, it is a bulge in the exhaust pipe just after the exhaust pipe is turned upwards, by the back shock. No bulge, no cat.
No cat's in all the North American 05s either.
(Canadian bikes don't have them and Canadian bikes were 49 state versions)
Overall, my recollection is this, but I might be wrong:
All California 919s had Evaporative Canisters.
At some point, the California bikes also got a cat', either in 05 or 06 and something about 06 rings a bell.
Then all North American 919s got cat's, pretty sure just one year only, in 2007, the last year of production.
It would be good to put this aspect to bed once and for all.
Another aspect of this is the North American ECUs and wiring diagrams across the years and variations.
As in whatever variations there actually were.