lewn did a nice job of outlining what you need to do.
according to stereophile your amp was available with a MC or MM pcb plug in board.
https://www.stereophile.com/content/creek-4240-special-edition-integrated-amplifier-specifications
key thing to know is not only how much gain each of the two board options offers, bit also what kind of loading is available. is the loading fixed at 100 ohm or do you have to solder resistors into the pcb to change loading?
once you have these answers you should be in better shape to determine what carts will work with your amp.
according to stereophile your amp was available with a MC or MM pcb plug in board.
https://www.stereophile.com/content/creek-4240-special-edition-integrated-amplifier-specifications
key thing to know is not only how much gain each of the two board options offers, bit also what kind of loading is available. is the loading fixed at 100 ohm or do you have to solder resistors into the pcb to change loading?
once you have these answers you should be in better shape to determine what carts will work with your amp.