I'm sorry, guys. I should've been more specific. I do not wish to structurally alter my older 66-1 in any way. I simply was searching from a fiber optic front sight to drop into the machined area on the front sight where the red insert used to be. Currently, my 66-1 wears long-since darkened Meprolight night sights and I'm just trying to update the gun for home protection for my wife.

Google searches have been fruitless and I know there are some genuine experts on this forum who could help with their knowledge. Thank you.