Gmail message shows actual upload date after import via Python script and not the date from the eml file

Question

the following Python script should import eml files which are located within a specific folder and assign a pre-defined label. In general the script is working and doing its job.

There is just one small problem, instead of the timestamp form the eml, in the Gmail interface I see the timestamp from the import. This way emails are not blended into the timeline correctly.

Is it possible to adjust the "Received:" date to the date from the eml as it was originally?

I thought I tackled this already by setting the "internalDate".

import os
import base64
import email
import json
import imaplib
from google.oauth2.credentials import Credentials
from google_auth_oauthlib.flow import InstalledAppFlow
from googleapiclient.discovery import build
from datetime import datetime

# Gmail API settings
SCOPES = ['https://www.googleapis.com/auth/gmail.modify']
CLIENT_SECRET_FILE = 'credentials.json'
GMAIL_USER = '[email protected]'

# Label to use in Gmail (e.g., "backup")
GMAIL_LABEL = 'backup'

# Directory containing your local .eml files
LOCAL_EML_DIR = './eml/'

# Define a function to get a Gmail API service
def get_gmail_service():
    creds = None
    # The file token.json stores the user's access and refresh tokens.
    if os.path.exists('token.json'):
        creds = Credentials.from_authorized_user_file('token.json', SCOPES)
    if not creds or not creds.valid:
        flow = InstalledAppFlow.from_client_secrets_file(CLIENT_SECRET_FILE, SCOPES)
        creds = flow.run_local_server(port=0)
        # Save the credentials for the next run
        with open('token.json', 'w') as token:
            token.write(creds.to_json())
    service = build('gmail', 'v1', credentials=creds)
    return service

def get_label_id(service, label_name):
    results = service.users().labels().list(userId=GMAIL_USER).execute()
    labels = results.get('labels', [])
    
    for label in labels:
        if label['name'] == label_name:
            return label['id']
    
    return None

# Upload local .eml files to Gmail using the Gmail API
def upload_eml_files_to_gmail(service, label_name, eml_dir):
    label_id = get_label_id(service, label_name)  # Get the label ID by name
    if not label_id:
        print(f"Label '{label_name}' not found in Gmail.")
        return

    for filename in os.listdir(eml_dir):
        if filename.endswith('.eml'):
            eml_path = os.path.join(eml_dir, filename)
            
            # Read the .eml file
            with open(eml_path, 'rb') as eml_file:
                eml_data = eml_file.read()
            
            # Extract the INTERNALDATE from the EML file
            eml_message = email.message_from_bytes(eml_data)
            internaldate = eml_message.get('Date')
            
            # Convert internaldate to Unix timestamp and then to an integer
            internaldate = datetime.strptime(internaldate, '%a, %d %b %Y %H:%M:%S %z').timestamp()
            internaldate = int(internaldate)
            
            # Create a message with the eml file content and internalDate
            message = base64.urlsafe_b64encode(eml_data).decode('utf-8')
            
            message = {
                'raw': message,
                'internalDate': str(internaldate),
                'labelIds': [label_id]  # Assign the label to the message
            }
            
            # Upload the message to Gmail with the specified label
            service.users().messages().insert(userId=GMAIL_USER, body=message).execute()

# Main function to run the script
def main():
    service = get_gmail_service()  # Authenticate with Gmail API
    upload_eml_files_to_gmail(service, GMAIL_LABEL, LOCAL_EML_DIR)  # Upload .eml files to Gmail

if __name__ == '__main__':
    main()

Original time stamp:

Gmail time stamp (shows the upload time):

Message header in Gmail (shows both time stamps):