A number of members here have talked about where to get adjustable sights (non-tritium) for their weapons.
The new CDNN catalog (and their website) has adjustable sights for the 75, 75B, 85 and 85B on sale.
The sights come in two forms: low mount adjustables (rear only), $25, and adjustable target sights (front and rear) $30. Includes, while they last, a choice of configurations: no markings, white dots, or white outline.
I just ordered an adjustable for my pre-B.
The factory adjustable sights on my 85 Combat and Kadet kit are virtually identical to the Mec-Gars that came on my custom 1911 (since replaced for night sights). I'm sure the same company makes both sights.
Good price and good place to do business. ($9.99 shipping for all items, up to 1000 items.) www.cdnninvestments.com
Do a search for "CZ-75 Sights" or "Mec-Gar Adjustable Sights"