If i go to primary care physician for an opinion of warts on my fingers, would that qualify as 'preventative care' for general insurance billing?

NO: Preventive Care is essentially a physical examination and discussion of routine testing you should get that is age specific for you (example colonoscopy at age 50 without a family history, etc.) Warts are classified as a specific medical condition and not related to prevention.

Wart treatment: You are asking for an opinion about treatment of a medical condition. If you saw your physician for preventive care checkup, you might use that opportunity to ask about your options for treating your warts. The usual options are chemical (daily topical application for weeks) or freeze the wart (takes just a second, requires liquid nitrogen), or burning (cauterization)