Hi Ezra,
There are 4 potential Check Layout reports you can choose from: Report 1401, 10401, 10411, and 10412 (see screenshot below).

If you check out Report Selections - Bank Acc. and choose Usage: Check, you will see that the default Check report is 1401:

Going back to the first screenshot, you will see that all four of the built in layouts are RDLC based, and none of them have pre-built Custom Layouts.
This doesn't preclude you from making your own Word based layout for one of these, but you'll have to start from scratch. RDLC offers greater flexibility / capabilities than Word layouts, but they are more complex to use.
If you decide that it's too much effort to start a Word layout from scratch, you might want to check this video out (on working RDLC to customize a layout): https://www.youtube.com/watch?v=ubGONIJSJgM
You can download and use the free SQL Report Builder 2014 or Visual Studio 2015 Professional / Community to work with RDLC layouts.
If you are working with a partner for Dynamics 365 for Financials, they may also be able to help.
I hope this helps! If my response has answered your question, please verify by clicking Yes next to "Did this answer your question?"