Shiny silver paint? No such thing. What you see on bare aircraft is bare metal (although it is AlClad). The reason is, on Airbus anyway, that in the early years the aluminum didn't match. On the L-1011, I suppose it's the same reason. When you see it on a newer airliner such as an AA DC-9-80 it is most likely one acquired from another carrier that had a painted tail. An aircraft can be polished to be nice shiny aluminum (reference AA A300s) though this is much more time consuming that actually painting an airplane. AA did it just so the A300 would look like the rest of the fleet.
BTW, the guys who operated the buffers to do this are not people you want to get in an argument with. Imagine holding a 35 pound polisher over your head 10 hours a day for a few years. THere are people who pay a gym for this abuse.
The day you stop learning is the day you should die.