Be advised that depending on which Red Dot you install you may need to replace the PSA tall front sight on the RK1 ( mine was .330 tall ) with a shorter front sight to get it to co witness. I needed a .215 tall sight or the red dot was centered inside the rear sight notch towards the bottom with a Holosun 507Kx2 ( the 407K will almost certainly be the same ). Ameriglo does have a .215 front sight available ( item # GLS215 ). Dawson Precision has a .220 tall fiber optic front sight for Glocks if you prefer. Luckily, you only need a Glock front sight tool ( a 3/16 hex nut driver ) to swap them.
PS, you have to be very careful in filing down the rear sight so as to make sure you don’t inadvertently change the 60 degree dovetail angle on the rear sight base. Dawson Precision does sell a one sided triangular file with a 60 degree angle for this purpose.