Yep, you could even make it with custom extensions.
Since you got here you probably own a vBulletin license meaning you can download it. So go download it, get the files in HTML version.
If you have cPanel, add this in MIME types:
application/x-httpd-php
For extension: html
Else, if you have access to Apache's Config (httpd.conf), add this line:
AddType application/x-httpd-php .html
Hope I helped