It depends. You usually have different services depending on which year it is. For example, many cars have a minor service at 1 year, 3 years, 5 years etc, and a major service at 2 years, 4 years, 6 years etc, with certain items to be changed at e.g. the 5 year service.
So if it is the first service, I doubt spark plugs should be changed unless there is a problem. But if it was the 5th year, then I would think they should.
Best place to look is the service logbook that came with the car. That usually says what gets changed when.