yes this is possible. I have recently done this tutorial and succeeded in customizing the title.
In my opinion the instructions in this part of the tutorial are hard to understand. Here is what I did:
1.0 Navigate to the project directory mysite/mysite/
2.0 Create a new sub-directory called templates. You should now have a directory mysite/mysite/templates/
3.0 Create a new sub-directory called admin in the above templates sub-directory. You should now have a directory mysite/mysite/templates/admin/
4.0 Edit the settings file (mysite/settings.py) and add a TEMPLATE_DIRS setting:
TEMPLATE_DIRS = [os.path.join(BASE_DIR, 'templates')]
5.0 Find the path of the django source files on your system.
To find this path open the python interpreter; import django and print the value of django.__path__ using the python command print(django.__path__)
6.0 On your file system navigate to the directory path obtained above from django.__path__ variable. You should see a directory called contrib. navigate to contrib/admin/templates/admin/
You should see a source file called base_site.html
7.0 Copy the above source file base_site.html into the directory mysite/mysite/templates/admin/. You should now have a file mysite/mysite/templates/admin/base_site.html
8.0 Edit the above file and replace {{ site_header|default:_('Django administration') }} (including the curly braces) with the new site name.
If the desired new site name is "My Company Name" then you should see
<h1 id="site-name"><a href="{% url 'admin:index' %}">My Company Name</a></h1>
9.0 Open the admin screen. You may need to refresh this page. You should now see that the label at the top of the page has changed.
There are a lot of steps - it is not a simple procedure.
Please let me know if above steps are clear, or if they can be improved.