It’s a very nice question. In short, if I say yes it is 50-50 means half of the course curriculum of both courses is the same.
For Fashion Photography and Portrait -Fundamentals of photography, Photography history, Camera and Camera Settings, Lighting, Framing & Composition, etc. will be the same in both the courses.
Apart from the above-mentioned topics, you will learn about what is a portrait, history about it, putting your subject at ease, backgrounds & posing, different types of portraits, editing of it in Adobe Photoshop and Adobe Lightroom in the Portrait photography syllabus. While in Fashion Photography you will learn about fashion photography, creative context, studio flash lighting, fashion study, photographing fashion accessories, posing as per the fashion industry and portfolio apart from the common syllabus.
Here I have given you the rough idea about the syllabus it may vary from institute to institute.