It has been said it does. I haven't experimented with it too much myself though. In all the mining I did on Head-Fi, it appeared the consensus was that if you must finish the cups, use something like linseed or tung oil. If you want to laquer/varnish them, do only the outside.
As always though, YMMV. I have seen very heated debates over smaller adjustments that really made no difference to me whatsoever.