Indeed, the simple response is affirmative. The TypeScript loader integrated with Webpack is expressly set up to utilize the tsconfig.webpack.json file. You can verify this at line 133 of the common configuration.
The presence of the tsconfig.json file is primarily for IDE support.
It's important to mention that although you mentioned the use of ts-loader in the template, it actually employs awesome-typescript-loader.
That being said, both loaders will attempt by default to locate a file labeled tsconfig.json, and this behavior is specifically overridden in the linked line within the template.
There are various reasons why multiple TypeScript script configuration files may be utilized in a project, but tools like Visual Studio Code rely on the one named tsconfig.json to enable features such as intellisense, configure options, and understand the project scope.
It is perfectly acceptable to use the same file for both purposes, which would be the default scenario.
Key Points
Please take note that the AngularClass template is quite complex and overloaded. Given that it serves as a launchpad from which you will likely build upon, the excess boilerplate and clutter that you inherit by starting your application based on this template should be carefully considered. This caution is particularly pertinent if you are new to any of the involved tools, transpilers, or frameworks.
In fact, I am a contributor to that repository. They accepted a pull request from me that addressed an issue with a utility function reported as confusing. Interestingly, I had removed that very function from our project long before submitting the PR to enhance it.
Having experience with a project derived from their templates, I spent significant time removing unnecessary Webpack configurations that hindered progress. In the end, we reduced the Webpack config to just around a hundred lines. While I have reservations about Webpack (JSPM advocate here), the template misused its potential. Countless superfluous tasks made Webpack appear more convoluted than necessary. The helpers file included was essentially pointless and unrelated to Webpack, TypeScript, or even Angular.
Also concerning is the fact that the angular class website markets training resources. There's nothing inherently wrong with this practice, but they introduce additional complexity beyond the already intricate toolchain.