Yes, Microsoft Teams does allow publishing white-labeled custom apps into their store. However, there are some guidelines and requirements that must be followed in order to publish an app in the Teams store.
For instance, all apps must go through a security and compliance review before they can be published. The app must also meet certain standards for user experience, functionality, and design. Additionally, there may be specific requirements for white-labeled apps, such as ensuring that the app is distinguishable from other similar apps in the store.
It's recommended that you review the Microsoft Teams App Submission and Validation Policy for complete information on the guidelines and requirements for publishing an app in the Teams store. You may also want to consult with a Microsoft Teams development expert or support representative for additional guidance on the app submission process.