Can Someone be Simply "An Agnostic?"

[MindForgedManacle]

...And do you think that your opinions are always true, or that they're just your opinions and may be wrong?

I'm sorry, but this is very simple: Your opinions are all the things you think are or are not the case. To give your opinion on anything is to say what you think is or is not true on that topic.

There's a difference between holding an opinion and believing it to be true; hence the labels "agnostic" and "gnostic" when it comes to religious belief or lack thereof.

No there isn't. If I hold an opinion that something is true, that is that exact same thing as saying I believe that something is true. Self-evidently, that doesn't mean it's true but that has not been something I've said.

And no. Labels like agnostic have to do with the apparent inability to justify any strong position on the claim that God does or doesn't exist.