If you encounter that the font is different than your document when you insert a field into a template, you should change the "Normal" Style font. To do this:

 

On the Home tab, right-click the Normal style in the Styles gallery and click Modify.

Word Modify Style

 

In the Formatting section, change the Formatting font and size and click OK

Word Modify Style Format

This will set the font for the template you are working in and will insert variables using that font into your template.