How about the fact that there is no code rejecting it means it can be used? I see a couple places where there are voltage limitations - but they are either for dwelling applications or for other luminaire types, but I could be missing something so please point out to me (or ask your engineer that seems to think there is a limitation) any section that does give restrictions in this area.
It only seems to make sense that if there were 480 volt luminaires in existence before and now with the conversions of newer technologies taking place that they would design something that will work in place of what was existing, it may take extra effort to get something listed though, but once you get it listed - how can it be rejected if used per listing?