FYI: The reason I asked this is because the valve stems are aluminum as are the stock valve caps. If you replace these with non stock caps that are NOT aluminum it can cause corrosion in the valve stems. Aluminum does not like to be in contact with non aluminum metals and doing so facilitates corrosion.

If you are going to use non aluminum caps you may want to wrap the valve stem threads with teflon tape (pipe tape). This will limit the contact between the two different metals. It will also seal the threads from moisture and corrosion.