A leaky cam cover will not let oil into the cylinders. Presuming you mean the sparky end bit of the plugs is getting wet, you sure its not wet with petrol, can look like oil when the plugs are black with carbon? The only way oil is going to get on the plug ends is if its getting past the rings or past the valve stem seals. If its been sitting in the rain/snow for a week then the dizzy, coil, ht leads and even inside the dizzy cap etc may be very damp. Take the dizzy cap off and give every thing a good spray over with WD40. Check you are getting a spark (or not) at the plugs first. Sounds like three plugs aren't firing hence getting wet with fuel.......Now you'll say its been garaged all the time.........
If its the outside of the plug (above the thread) thats wet with 'oil' then it may well be the camcover gasket leaking into the plug wells, but that wouldn't necessarily prevent the car from starting unless the wells were really flooded. Check that the breathers are all clear, if blocked they can force the camcover gasket to leak or push oil out of the dipstick..........
