Countries like Israel should also be encouraged to to disclose their number of nuclear weapons, aswell as signing up for the NPT. No doubt most countries overestimate their number of nukes, partly because its become a global dick waving contest.
Israel will not allow any outsider to inspect their nuke stockpile. Not even the Americans will be permitted anywhere near the nukes (although they had bought these weapons from the US). But at the same time, they have no issues in asking DPRK and Iran to get their nukes inspected by the International Atomic Energy Agency (IAEA).
What else would you expect? Don't you want to know if Iran or North Korea have nukes?
Israel is no enemy.