I'm not 100% sure that all CIH engines with the dipstick hole in the block have the internal tube. I had a factory 2.0 engine that was supposed to have it, but it was also missing from my engine. I didn't know it was supposed to be there either until later. I could wiggle the dipstick and feel it rubbing the side of the crankshaft while the engine was running. I had trouble with that engine leaking oil out of the dipstick hole and the stick not fitting good. My 2.4 does have the tube, but, before it was rebuilt, it had the blowby which would slowly push the dipstick out of the block.
Later or this weekend I will take a picture of the tube in my faulty 2.4.