No, I don't think that is really the case. The responsibility (blame?) I think rests on California, primarily. Remember the discussion about early and late MY production awhile back? Spyders produced in May, or whatever the time frame is, are labeled early models. Quite possibly, the emissions info on those models was not reviewed and certified by CARB before BRP was ready to put them into the market pipeline. Maybe, and this is just my speculation, since the early 2021s were essentially the same as the 2020s BRP thought the 2020 CARB cert would cover them. And maybe that's what has happened in the past. Who knows, maybe there is a new 'strictly by the rules' head of CARB who kiboshed that old practice. One thing we know for sure, BRP nor CARB will ever clear up the mystery for us.
As I see it it's not a matter of BRP building separate 49 state and CA state models, but a problem of getting a CARB cert in a timely fashion. Without the EO in hand BRP could not push the Spyders out the door as CARB certified, even though the CARB cert causes no changes whatever to the physical machine. The fact that the first digit of the VIN is different between the CARB and non-CARB may be more of a record keeping action and a way to prevent non-CARB machines from having their manufacturing info massaged to make them look like CARB machines.
I think in this case the only difference between CARB and non-CARB machines is the label that is allowed to be affixed to them, and the first digit of the VIN.