Yes—when a lens is stopped down, the bundle of rays narrows, so light generally uses only the central part of lens elements behind the aperture blades, assuming those elements are already large enough at wide open.

A donut-shaped mask on the rear element can affect the image, depending on whether its opening is smaller than the light cone coming through the aperture. If the mask blocks part of that light cone, you’ll reduce light, likely add vignetting, and may degrade image quality. Reported effects include dimmer exposure, increased flare, and softer or poorer focus; the exact result depends on the size of the hole and the material used. Dark material is less likely to add flare than white material.

In normal lens design, the iris is placed so it controls the light bundle without unnecessarily vignetting the image. So stopping down already limits which parts of later elements are used; adding an extra mask near the rear element usually just blocks light and can introduce unwanted optical side effects.