I would worry more about the quality of gasoline in the tank. Lot of gas has Ethanol in the gas and it has a very short life cycle and separates and can gum up Carb and fuel lines over a short period of time. It can also rot away fuel lines from the inside out if the lines are not ethanol friendly. Like many say do not put your car away wet. Drain or run the fuel system empty.

Oil lasts and lasts. Take a look at how clean it appears and go from there. Oil is cheap if you feel better changing it do it.