Yes, you can check the theme settings and sections on trial version. For example - If you want to check Homepage section - Please try the theme >> Online Stores >> Themes >> Customize
On trail period - they will not provide you code access to edit it.
Nick here from Shopify.
I spoke to a theme partner advocate from Shopify about this to find out as much as possible for you.
The theme partner advocate mentioned that filters are set up within the admin of the store. The theme only displays the content that is set up as filters. In the settings in the Theme Editor there is usually a read more or info link to take you to the specific support help documents for each theme to offer some details on setting up filters within Shopify. Together with those support docs and another one here about searching for products and filtering your product list, it should allow you to test out the filters you have set up with your products/collections/swatches, etc.
Something else to remember is that the trial period has an unlimited testing time for the theme (this is unlimited as we need you to be sure that this is the theme you want as themes are non-refundable purchases). This way you can be 100% that this is the theme you want.
Hope this helps!
All the best, Nick