It could happen. Dust is not unusual, people have had it in new cameras. It would not be dust on the lens making tiny spots like that. Dirt on the lens would need to be extensive and would cause more of a not so clearly defined bad effect in the image. Here is a little article that shows sensor dust and lens dust.
How to Spot Dust on Your DSLR Sensor
DIY sensor cleaning is not a big deal, plenty of threads on it here and elsewhere, but I don't have any links handy. There is a good video that I have seen posted here many times.
How to Spot Dust on Your DSLR Sensor
DIY sensor cleaning is not a big deal, plenty of threads on it here and elsewhere, but I don't have any links handy. There is a good video that I have seen posted here many times.