Do these covers work with the factory door locks?

Yes. The keyhole opening allows you to use your key normally. You're covering the handle itself, not blocking access to the lock cylinder.

Will I need fasteners to install these?

The covers mount at factory points, so you'll likely reuse your existing hardware. Confirm bolt size and condition before installation—you may need new bolts if originals are damaged.

Do these require paint or primer before install?

Installation method and finish aren't specified. Test-fit before deciding on paint or protective coating—verify the finish matches your needs or plan surface prep accordingly.