I've never received an AMP email but it looks like based on the format [1] one could search the body for cdn.ampproject.org and either REJECT, DISCARD in Postfix or quarantine it if using some anti-spam platform.

    # grep body main.cf
    body_checks = regexp:/etc/postfix/body_checks

    # grep ampproj /etc/postfix/body_checks
    /ampproject/    REJECT AMP IS NOT SUPPORTED ON THIS SERVER

[1] - https://amp.dev/documentation/guides-and-tutorials/learn/ema...