Hi Erin,
The answer is yes. Alterations can be done by anyone who opens the design file. If they have the catalog that the design was created with, they will be able to modify the items. If they do not have the catalog your design was created with, they will not be able to modify those items and they most likely would not be able to see them in a 3D rendering. They would still be able to remove items, dimensions, or anything you can do.
Regards,
Kris