To answer the insert-pop-up question, here is an illustration of a Cook Islands item. Goldplated copper "coin", with a silver plated "pop up" feature.

Two planchets, one as an irregular shape die cut out, witha small rectangle at the bottom edge, which fits into a rectangular depression in the coinbase.

This is a specialty of the Mayer Mint (a private mint doing many NCLT issues)

To visit the Mayer Mint web site, see:
www.mayermint.com

To read the earlier E-Sylum article, see:
QUERY: THE COOK ISLANDS POP-UP COIN(www.coinbooks.org/esylum_v17n42a19.html)