The old BRNO match sights like I have on my CZ 452 Ultra Lux mount to either 11mm (CZ 452) or 16mm (CZ 527) rear scope dovetails, using a removable adapter. The front globe uses and a mount that slots into the keyway the front sight post rides in. I don't have a 527 with sights to test fit it on, but it's worth checking out.