Jobs at small Wichita companies nobody posts about after 13 years as a mechanic

Two small Wichita employers told me they are hiring but have not posted yet. I have read a lot of threads here and could not find my exact situation. They like a brief email with a résumé. Should I visit in person?

A short email with two sentences about what you can do and your résumé attached worked for me. I followed up after a week.