theoretically yes. If you use kiwi polish, the wax in it will soak itself into the pores that allow the boots to breath (and stop you sweating), and all that money you spent on a nice goretex liner will be wasted.
it depends what you want to use them for? if they're for the field only, you can use Nikwax cleaner and conditioner to make them look good and black without stopping them breathing. if they're for wearing in camp, you may want to consider using it anyway to keep people off your back. Nikwax ain't bad though, once you've used the first pot of it they start to look like polished boots.