It depends, if you're doing commissioned job for a client, then yes, you can buy a model with royalty free licence, print it, or mill it on CNC and give result as the part of the job to the client. On the other hand, if your plan is to make multiple physical copies of that object and offer to buy for your customers, then the answer is no, such activity is prohibited by the royalty free license. Distributing digital files in the form that you downloaded them is not allowed in any case. If you have more questions or need clarification, i suggest you to contact site support, they might be qualified to give you legal advice, or might be not, but some random dude on the forum certainly isn't.