I was finally able to snag an earlier (1966) Brno ZKK600 with the peep sight in the rear bridge (I'm in the U.S. so these do not come up all that often for sale). This guy has the rounder more continental looking stock, rather than the more square rosewood tipped version. Sadly, the front and rear (barrel mounted) sight are missing. I'm thinking that a CZ 550 sight blade insert may fit in the ramp. Has anyone tried this before and if so, do you have any idea what sight height I should look to buy to make it functional with the peep? I guess the CZ sight inserts are marked with numbers on the base corresponding with a certain height, but I'm not sure if Brno did this or not.

Also, I don't imagine I'm going to be able to find a Brno original ZKK rear sight for the gun, but are there any rear sights out there that are close in appearance? Maybe something generic, or perhaps NECG?