trans | Volunteering Disclosure

I'm planning to volunteer at a local historical society this summer, and I'd really like to present as male while doing so. The application for volunteering has both a spot for legal name and name preferred for name-tags and records, but my preferred name is not obviously male. Should I disclose my trans status at the time of applying, or wait to see how they react to my application first? Or is this a bad idea and I should just present as female? I pass iffily - people believe me if I'm explicitly introduced as male, but they tend not to peg me as such otherwise, though I suspect that will get better after I get a haircut. Any thoughts/suggestions/advice would be wonderful.