Custom Font in Document Generation API

We have a .docx template which is being merged with some JSON data and turned into a PDF via the Document Generation API. We are using the .NET SDK for this.

Most of the document template is formatted in "Montserrat" font which seems to be a non-standard font type. When we get the resulting PDF, it appears to have converted all the Montserrat into Calibri font.

Does anyone know if Montserrat font is supported by the Document Generation API?