I admire your ethics--your concern about the commission.
First, with whomever you deal with, be absolutely honest. Explain what your strategy is. It's entirely possible you';ll get an agent to show you the property anyway. They'll figure, perhaps correctly, that you might like the home so much that you're willing to make an offer on it now. Or that you won't succeed at auction, but will be interested in using their services for another property.
As for whether to make that request of the listing agent . . . I'd advise against it. The listing agent represents the seller, not you. In many areas of the country (I don't know about California) it's entirely legal for an agent to represent both parties. And, with full disclosure, it's perfectly ethical. Still, as a practical matter, it doesn't serve your interests as well as having your own agent.
As for paying a fee: Sure, that's a possibility. Whatever agreement you and the agent agree to should work.
Bottom line: As your instincts suggest, don't mislead the agent. Be absolutely honest. But I'm sure that you'll be able to work something out.
Hope that helps.