Here's the thing. The moment you create an artistic work, in the US and most other countries, its automatically copyrighted, and you are a copyright owner. Copyright registration just makes it easier to prove ownership in court, but otherwise gives you no other benefit.
You have every right to put a copyright symbol on your own work. If you put your name on the manual and have ID on you, you can probably get the Stinkos cop to lay off. Or take your business elsewhere.
In addition, all copy places should have a standard release form for you to sign which is you stating that you may legally copy the work in question, which leave them off the hook.