There are probably several things you should do to evaluate the camera for dust. You'll need a Rocket Blower or something similar. I don't think you need to send it for cleaning unless you have a problem.
I would probably start with a visible examination for dust and some test images. Check for visible dust or other materials in the body. Turn the camera so that the opening points toward the ground. Use the blower to remove anything that is visible, and for anything small that will fall out.
I test using a plain sky - clear or overcast - and f/22. Upload the images and look for dust spots - small round circles that are slightly darker than the surrounding area. If there is no problem, don't worry about it.
The two main places dust shows up are the mirror and the sensor. Use the blower to make sure there is no dust on the mirror. Then use the blower on the sensor.
If you have dust on the sensor, you'll need to clean the sensor. The first approach is to use the blower. If that does not work, a wet cleaning is going to be required. You can do-it-yourself or send your camera to a shop or repair service for cleaning. And send it with the body cap in place.
Look through the viewfinder to see if there is any sign of dust. It's possible you can get some dust on the prism in the camera viewfinder. While this is not un usual, it's hard to remove. I'd try the blower to see if it falls out. The good news is it won't affect your images.
Take some more test images. If there is no problem now you are ready to shoot.