While some CZ have come with Tritium sights, most CZ factory sights are NOT true night sights. Most CZs come with conventional sights with light-reactive paint on the dots. If illuminated by bright light, they will glow for a while in the dark, but they aren't true night sights.) The box will say "tritium night sights" if they're truly night sights -- and they'll glow in the dark without first being illuminated.
The CUSTOM SHOP, as already noted, is a good place for CZ sights.