Click on the 3 dots in the post's top right corner and click Timestamp it. You just need to wait for the block confirmations. :)
#Amethyst feature request: Timestamp posts with blocktime 😁 nostr:nprofile1qqsyvrp9u6p0mfur9dfdru3d853tx9mdjuhkphxuxgfwmryja7zsvhqpzamhxue69uhhv6t5daezumn0wd68yvfwvdhk6tcpz9mhxue69uhkummnw3ezuamfdejj7qgwwaehxw309ahx7uewd3hkctcscpyug
Click on the 3 dots in the post's top right corner and click Timestamp it. You just need to wait for the block confirmations. :)