The OP didn't specify, but I'm assuming that he's looking at the left hand 452 American that CZ kept in production when they switched to the 455.
If the OP is looking at an American, the rail is 3/8. But, a quick google search of 'cz 452 american dovetail size' will show the experiences of lots of people who have had difficulty putting 3/8 dovetail rings on the CZ 3/8 dovetail. Some rings work, some rings don't. I know that I had a set of 3/8 rings that sat cockeyed on the cz dovetail. Ended up using adapters from J&P gunsprings to mount Burris Signature Zee rings.
Talley makes a set of 3/8 dovetail rings specifically for the 452/453
https://www.talleymanufacturing.com/...-talley-rings/
Maybe people can share what rings worked on the 452/453 American for them.
Not sure why CZ didn't just stick with their 11mm dovetail on all versions of the 452
CZ dovetail info
