No source, credible or otherwise, attempts a monetary figure for the statue or the temple building specifically. Only the far broader Crown Property Bureau, of which the temple is one holding among many, has drawn outside estimates, and those cannot be read back onto the temple itself.
What would resolve this A statement from the Bureau of the Royal Household or Crown Property Bureau isolating a value or insurance figure for the Emerald Buddha or Wat Phra Kaew specifically, apart from aggregate crown-property estimates.
OpenThai royal and crown-property administration, and cultural heritage appraisal.Temple of the Emerald Buddha (Google Arts & Culture)