Strictly speaking, the "Gujarati font" cannot exist, just because Gujarati uses Nāgarī writing system which is also used for Kutchi:
However, it's probably due to popularity of Gujarati the relevant Unicode sub-set is called "Gujarati" in Windows "Font Viewer".
Anyway, you don't need something like "Gujarati font" or even "Nāgarī font". I'm not even sure such fonts exist, because this is not how Unicode works. The fonts usually contain many Unicode subsets per single font; and Gujarati (Nāgarī) is so popular that it is supported by default by most modern system. I, for example, can type Gujarati on my system where I did not install anything except the US English locale; the same goes for all my Windows and Linux systems.