Our greenline came without the spoiler as well. The dealer noticed this after he brought it up from another dealer. What he told us was that the spoilers are not put on until after transport to the dealers lot.

I don't know how much of an improvement you get with the spoiler, but if IIRC it is attached without drilling so you may be able to remove it later without any holes. (Check with the dealer first on that). You may be in a better position to tell us what gain the spoiler gives if you go this route.