Firstly the crystal face is a replacement grille and doesn’t cover the existing grille. Regarding insurance anything you order from the factory is covered as part of the car. The only time RSA ever had issues is when I tried to add a factory spoiler and I needed specific permission as it was classed as a performance modification. I never order a standard car and never had an issue with insurance cover when I’ve had accidents. It’s a standard fleet policy which takes account of the variations in people’s orders. What won’t be covered is anything you add after purchase that affect performance or warranty. That’s why you’re not allowed to hard wire a dash cam as it’s classed as tampering with the integrity of the car.
Everthing has got to insured to some extent but, from my understanding your spoiler albeit fitted at the factory would only be covered by “third party insurance”. In the event of an accident the cost of your spoiler or any other optional extra, will be down to you or in the event of a write off you would loose the additional cost of these, which is not to different to private insurance.