def is_last_ts_in_thousands(timestamps):
    """Detect if the last timestamp in a sequence is a multiple of 1000.

    Args:
        timestamps (list): An list of timestamps (in picoseconds).

    Returns:
        True if the last timestamp is a multiple of 1000, False otherwise.
    """
    if timestamps is None:
        return True

    last_timestamp = max(timestamps)
    return last_timestamp % 1000 == 0