Headlamp retaining rings.

Anyone know where I can get the mounting retaining rings that hold the headlamps? Mine are pretty badly corroded to where they flex easily and the retaining bracket and screws are rusted tight.

*Added* I probably should have mentioned it's a 68 Barracuda, in case that matters. I would guess all A bodies have the same headlamp as I've found them on shelf at an AutoZone recently, but I am unsure of that.