If they could prove it was more restrictive than the inserts in Sahara and Rubi, then maybe, but most inserts I’ve seen are pretty much a copy of the stock ones.
I’d suggest that if there’s any sort of issue requiring warranty service that could possibly be impacted by a grille insert, that you simply remove it and put the stock grille insert back into place before seeking warranty service. Although I can’t see anything that would be affected by it other than if it restricts airflow and causes overheating. In which case I’d hope you’d take it off before it causes problems.