There is a trade off to be made here to be honest. The screen has the anti-glare coating which is working very well in my opinion. The protective film will certainly degrade the performance of the coating so that the reflection will be very annoying especially when you put the roof down. On the other hand though, although I don't know how the scratch happened, but since you've had that, that means the coating and the screen need some protection.
I personally is in the no film group. None of my phone, tablet, cars or anything with a screen has the film applied. When my G31 is used to transport anything that may damage the screen, I just wrap with a cloth or bubble wrap. :rofl: I cound't find a similar usage scenario for the G29 so never consider the screen protective film at all. Plus, the protective film for our cars sold in UK are just so expensive.