The iron valve guides on many old cars, particularly valve-in-block engines, are very long and have a lot of surface area along the stem of the valve. In damp storage these long guides can rust up, but not if the car is well oiled and stored properly. Never heard of this happening on a TR engine, though, but it's always wise with a long-stored engine to turn it over by hand before running it. Easy to pop the valve cover and rocker arm assembly off to have a look at things and give them a shot of oil. A mild rap on the end of the valve stem with a hammer and brass drift or block of wood will verify that the valves are free. More troublesome, of course, is if the valve seats have rusted over time.