Or you can buy flattening agent (most paint manufacturers have this additive in their line for the appropriate base paint) to add to a normally glossy paint.

Also, the paint manufacturers actually make a flat, or semi-flat, black. For example, John Deere and Caterpillar have flat and semi flat blacks in their specs, so any paint manufacturer who has a paint code for those can supply it.

Both these alternatives will be more durable than non cleared base coat which is formulated to be buried (or protected if you will) by clear coat. Most quality top coats contain a UV light inhibitor to reduce the chance of sun fade. Base coat alone doesn't contain that protection.