Common casting, all Siamese, unfortunately there haven't been any water blocks since the prior generation piece marketed as 'megablock'.
I built a cast iron World block back in the early 2000s with the 4.190 rough bore block bought from Mopar per the customer not wanting to take a chance on the larger 4.490 bore block running hot, he ASSUMED that the smaller bore block would have water passages between he cylinders, NOT SO
There may have been around 1.0 to maybe 2.0 inch small opening, part of a very small water passage, down low on the center cylinders, maybe not
