yes, 27.0/30.0 (29.5 for interference) is JIS.
Stack heights vary by brand and model. But IME the stack height of any model is the same whether it's the ISO or JIS version. There's no set height, with some models being in the low 30s and others as much as 45mm. Unless otherwise instructed I cut forks for 45-46mm stack height, and use spacers for shorter headsets. That allows for a change to a taller brand later on.
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