The Trijicon CA23 WILL fit the CZ40P/B, but some elbow grease is required in that the CZ40P/B sights have a small notch on the bottom so that the hammer won't be stopped by the sights. (
http://www.czfirearms.us/index.php?topic=47111.0).
MAJOR UPDATE 2: "CA23 will fit the pre XS as well as the XS models Officers and CCO/Commander." So I'm 99.9% sure that Trijicon CA23 WILL WORK ON THE CZ40P/B!!!!!!!!! HALLELUJAH!!!!!!!!! Now to hear it straight from the horse's mouth...
MAJOR UPDATE: So I've been lurking around Colt forums some more and I found that the 'Enhanced' Colts are not of the XSE line so they actually may use the same sights as the CZ40P! The early versions of the Colt CCO (Concealed Carry Officer) used the proprietary Colt sights before the XS line even came to be and if this review for the Trijicon CA23 (Enhanced Officers/Combat Commander) is to be taken at face value (title of the review reads "Defender night sights for Colt CCO"), it would seem that the Trijicon CA23 will indeed fit on the CZ40P/B!!! Mind you, I would call Trijicon and Colt to double check.
Sorry for the double post, but I did some digging on the sights on the CZ40P and I found out that they are proprietary Colt competition sights by C-MORE, which have been discontinued since around 1998. As such, we CZ40P owners are pretty much screwed out of any chance of proper night sights without having to drill and drop in tritium via tooltechgunsight. On the other hand, XS Sight Systems seems to have the sights available for the Colt Defender under the Colt Competition section (
https://www.xssights.com/Products.aspx?CAT=8433), which I assume means that they are the very same Colt propriety sights that are on the CZ40P/B.
EDIT: The proprietary Colt competition sights are on all Colt XS models, which have been discontinued and replaced with the XSE line, which do not use the proprietary Colt sights. I checked out the Colt section of Trijicon (
https://www.trijicon.com/na_en/products/product2_bntns.php?mid=4) and saw that they use the photo of the Colt XS sights for the Enhanced Combat Commander, Enhanced Government, and Enhanced Officers, which are all of the XSE line. So Trijicon may or may not have some sights for the Colt XS line lying around, but I wouldn't get my hopes up. I also found that Heinie used to make sights for the Colt XS line, but discontinued it because they weren't tight enough; nevertheless, they are still in high demand and look pretty good (
http://www.thefirearmblog.com/blog/2009/11/30/daniels-1911-pistols/).
