Yes, the said gifts shall be treated as supply as per Schedule 1 of GST Act and has to pay GST at applicable rate on Gold Coins on the market value also. You are eligible to avail input credit on inward supply.
As per Schedule 1 it's taxable supply & As per Section 17(5) ITC is not available.
Even though its value exceeds 50k & cover under the taxable supply but its nature of supply is Gift & section 17(5) block credit by way of giving gift.