Headset labeling - Does this qualify as EC30?
30.03mm is a measurement one might expect to get off the OD of a 1" JIS cup (called EC29 in SHIS, from the 29.8mm frame bore). That's consistent with the "22.2/30.0/26.4" on the label.

However, 26.4 is the ID of a typical crown race from a 1" ISO/Campy/Professional headset, aka EC30. 

You are in possession of a mixed standards headset. These have always been around because some bikes actually come with a mixed standard on their parts, for reasons I can only speculate on. In SHIS parlance this would be EC29/26. The cup size plus a forward slash followed by the SHIS name for the crown race size is how this is communicated in SHIS.

In pre-SHIS days (SHIS is young in the history of bikes), the "22.2/30.0/26.4" label would be the piece of information that communicates this mixed standards configuration. It is naming the physical sizes of the parts, not the frame fitment. It's kinda implicit that this is the case when you look at it, but for a tricky reason: the way the numbers line up, as you've noticed, "30.0" could be taken as either the OD of a JIS cup or the ID of an ISO headtube. This has always thrown people for a loop. But 26.4 is only the ID of an ISO race, as a JIS race is the very different 27.0, so it should be assumed that the label is stating the dimensions of the parts inside, not the frame/fork dimensions.

Mixed standard headsets are pretty obscure, so this is an understandable mistake on the seller's part.