My 23 says .40sw on top right of flat top portion of chamber, and .40 S&W on the slide.
Its an old model, no finger grooves, no acc. rail. BHHxxxUS serial. It was purchased in like 94-95 area.
Edited to say....I haven't checked my model 27 to see what it lists as caliber, but will (its in the car and I'm too lazy).