Do I Ask My Potential Employer For Access to Clients CMS During Trial Task?

I have been asked to create a landing page for a client as part of an application process for a junior job. I was provided with the site and I also know they use WordPress however I was not provided with access credentials to the site's CMS. Would it be unprofessional for me to ask access to the site in order to create the landing page or am I expected to simply create the content in a word doc and send it through or even create a mock page using HTML5. I have experience with WP. Any Advice?